Carbs for a diabetic

How to Count Carbs for Better Blood Sugar Control

Learn more about the program >>

Your doctor may have told you to “count carbs” or use something called the glycemic index to plan your meals. A healthy diet consists of a balance of carbohydrates, proteins, and fats. However, people with type 2 diabetes need to watch carbohydrates carefully. Why? Because when any food that contains carbohydrates is digested, it turns into sugar, which increases your blood-glucose level. It’s pretty basic: Eating too many carbs can raise the amount of sugar in your bloodstream and lead to complications. The key for people like you with type 2 diabetes is to eat carbs in limited amounts at each meal and when you snack. Total carbs should make up about 45 to 60 percent of your daily diet (and be spaced out throughout the day) if you have type 2 diabetes.

There’s no one diet that works for everyone with type 2 diabetes — there are just too many variables: Age, weight, level of physical activity, medications, as well as daily routine and personal preference need to be taken into account. So here’s where your diabetes care team comes in: Talk to your dietitian or diabetes educator to determine the right carb-counting number for you so you’ll be able to provide your body with a steady flow of energy throughout the day, maintain a healthy weight, and manage your blood sugar.

Get Smart on Carb Counting

Get Smart on Carb Counting

Carbohydrate counting, or “carb counting,” helps many people with diabetes manage their food intake and blood sugar, and it’s most often used by people who take insulin twice or more times a day.
Carb counting may give you more choices and flexibility when planning meals. It involves counting the number of carb grams in a meal and matching that to your dose of insulin. With the right balance of physical activity and insulin, carb counting can help you manage your blood sugar. It sounds complex, but with help from a registered dietitian nutritionist (RDN) or certified diabetes educator (CDE), you can learn how to find the right balance.

How much carbohydrate?

The best place to start is to figure out how many carbs you are eating at your meals and snacks now. Tracking your food intake and your blood sugar before and about 2 hours after your meals for a few days can provide useful information for you and your diabetes care team to see how different meals impact your blood glucose and determine the right amount of carbs.

What foods have carbohydrate?

Foods that contain carbohydrate or “carbs” are:

  • grains like rice, oatmeal, and barley
  • grain-based foods like bread, cereal, pasta, and crackers
  • starchy vegetables like potatoes, peas and corn
  • fruit and juice
  • milk and yogurt
  • dried beans like pinto beans and soy products like veggie burgers
  • sweets and snack foods like sodas, juice drinks, cake, cookies, candy, and chips
  • Non-starchy vegetables like lettuce, cucumbers, broccoli, and cauliflower have very little carbohydrate and very little if any impact on your blood sugar.

Reading food labels will tell you how much carb is in foods that tend to be processed. Foods without labels such as fruits and vegetables are often better options and you can learn to estimate how much carbohydrate is in it.

Protein and fat

With carb counting, protein and fat in meals are also a factor but have less impact on your blood sugar than carbohydrates. Foods high in protein often contain fat, and both protein and fat can affect your blood sugar. While there is currently no clear method of counting grams with protein and fat to predict impact on your blood sugar, if you notice unexpected outcomes in your blood sugar when you eat foods high in protein and/or fat, talk with your diabetes care team about the best way to plan for those meals.

Using food labels

Carb counting is easier when the information is on the food label. You can look at how much carbohydrate is in the serving of food you plan to eat. The two items on the label that are most useful are the serving size and the total carbohydrate amount.

  • Look at the serving size. All the information on the label is about this amount of food. If you will be eating 2 or 3 servings, then you will need to double or triple the information on the label.
  • Look at the grams of total carbohydrate.
  • Added sugars and other bullets below the total carbohydrate listing are included in the total carbohydrate. They are called out to provide more information about what you are eating.
  • Finding the right balance of carbs, calories and portions that will satisfy you can take time and may also change as other factors in your life change.

Insulin-to-carb ratios to calculate meal insulin doses with type 1 diabetes

Some children and teens want or need options in meal planning. Using an insulin-to-carb ratio is a way for you to get the right amount of insulin for the carbohydrate you eat if you are not sticking to a carbohydrate pattern. Then you can eat different amounts of carbohydrate at each meal.

Use an insulin-to-carb ratio if you:

  • Are not sure your very young child will eat all the carbohydrate in the meal
  • Are not hungry
  • Do not like some foods served with a meal
  • Are eating a meal with a lot of carbohydrate
  • Are eating a low carbohydrate meal
  • Need or want a larger snack

The insulin-to-carb ratio means you will take 1 unit of insulin for a certain amount of carbohydrate.

For example, if your insulin-to-carb ratio is 1 unit of insulin for every 10 grams of carbohydrate (written 1:10), you will take 1 unit of insulin for every 10 grams of carbohydrate you eat.

To use an insulin-to-carb ratio, you need to:

  • Plan ahead and eat all of your meal.
  • Take your rapid-acting insulin 15 minutes before you eat.
    • The only time it is okay to take the rapid-acting insulin after eating is for very young children who may not eat everything. If a child is taking their insulin after they eat, they must take it as soon as they finish eating, within 30 minutes of their first bite of food.

Taking insulin after eating will always result in a high blood sugar a few hours later.

Taking insulin before eating and then not eating all of the planned carbohydrate will result in a low blood sugar when the rapid-acting insulin peaks.

If you will be using an insulin-to-carb ratio to calculate rapid-acting insulin doses, you will need to be accurate at counting carbohydrate and doing math to calculate your dose.

Practice using an insulin-to-carb ratio

When using your insulin-to-carb ratio, you divide the total grams of carbohydrate by the ratio amount.

Practice 1

  • Your breakfast dose of rapid-acting insulin is 1:10.
  • You plan to eat a total of 55 grams of carbohydrate for breakfast.
  1. Divide your total grams of carbohydrate by your ratio of 10. So 55 ÷ 10 = 5.5
  2. Your breakfast dose will be 5.5 units of rapid-acting insulin.

Practice 2

  • Your lunch dose of rapid-acting insulin is 1:20.
  • You plan to eat 55 grams of carbohydrate.
  1. Divide your total grams of carbohydrate by your ratio of 20. So 55 ÷ 20 = 2.75
  2. Round up to the nearest half unit. 2.75 rounded to the nearest half unit is 3.
  3. Your lunch dose will be 3 units of rapid-acting insulin.

Your ratio may be the same or different at each meal. Using an insulin-to-carb ratio of 1:10 gives you more insulin than if you use a ratio of 1:20.

When deciding whether to round up or down, think about:

  • Rounding up if your blood sugar is high
  • Rounding down if your blood sugar is low
  • What you will be doing in the next few hours, such as being active or sitting around

This can be confusing at first, but doing the math can help you understand this better.

Changing the insulin-to-carb ratio

You will have to do some math to figure out how to change your ratio. The diabetes nurses will teach you how to do this. It will not be perfect at first. It will take some time.

Things to remember in order to change insulin doses:

  • If the pattern happens at the blood sugar check before breakfast, change the long-acting insulin dose by 10 percent.
  • If the pattern happens at the blood sugar check before lunch, change the breakfast rapid-acting insulin dose by 10 percent.
  • If the pattern happens at the blood sugar check 2 to 3 hours after lunch, change the lunch rapid-acting insulin dose by 10 percent.
  • If the pattern happens at the blood sugar check 2 to 3 hours after supper (before the bedtime snack), change the supper rapid-acting insulin dose by 10 percent.
  • If your blood sugar is above 180 two to three hours after a meal, ask yourself what caused this.
    • Common reasons for high blood sugar 2 to 3 hours after eating are:
      1. Not taking insulin at least 15 minutes before eating
      2. Eating too much carbohydrate or too much quick-acting carbohydrate
      3. Not taking enough insulin to cover the carbohydrate
      4. Not eating protein or fat in your meal
      5. Eating a very high fat meal

If you rule out numbers 1 and 2, you may need to take more insulin next time.

  • If the pattern is high blood sugar, you will increase the insulin dose that affects that column of blood sugars.
  • If the pattern is low blood sugar, you will decrease the insulin dose that affects that column of blood sugars.

Treatment of Diabetes: The Diabetic Diet

The mainstays of diabetes treatment are:

  1. Working towards obtaining a healthy body weight
  2. Establishing a diabetes diet plan; no one diabetic diet fits all
  3. Fitting in daily physical activity, even walking is enough
  4. Medication, if needed

Note: Type 1 diabetes must be treated with insulin; if you have type 2 diabetes, you may not need to take insulin. This involves injecting insulin under the skin for it to work. Insulin cannot be taken as a pill because the digestive juices in the stomach would destroy the insulin before it could work. Scientists are looking for new ways to give insulin. But today, shots are the only method. There are, however, new methods to give the shots. Insulin pumps are now being widely used and many people are having great results.

In this Article

  • The Diabetic Diet
  • Understanding Food Groups

Working towards obtaining ideal body weight
An estimate of ideal body weight can be calculated using this formula:

For women:
Start with 100 pounds for 5 feet tall. Add 5 pounds for every inch over 5 feet. If you are under 5 feet, subtract 5 pounds for each inch under 5 feet. This will give you your ideal weight.

If you have a large frame, add 10%. If you have a small frame, subtract 10%. A good way to decide your frame size is to look at your wrist size compared to other women’s.

Example: A woman who is 5′ 4″ tall and has a large frame
100 pounds + 20 pounds (4 inches times 5 pounds per inch) = 120 pounds.
Add 10% for large frame (in this case 10% of 120 pounds is 12 pounds).
120 pounds + 12 pounds = 132 pounds ideal body weight.

For men:
Start with 106 pounds for a height of 5 foot. Add 6 pounds for every inch above 5 foot.

For a large frame, add 10%. For a small frame, subtract 10%. (See above for further details.)

Learn More about Treating Type 2 Diabetes

  • Type 2 Diabetes and Exercise
  • How to Lose Weight with Type 2 Diabetes
  • Medications for Type 2 Diabetes
  • Type 2 Diabetes and Insulin

The Diabetic Diet
Diet is very important in diabetes. There are differing philosophies on what is the best diet but below is a guideline with some general principles.

Patients with type 1 diabetes should have a diet that has approximately 35 calories per kg of body weight per day (or 16 calories per pound of body weight per day). If you have a child who has type 1 diabetes, we encourage you to read our article about meal planning for children with type 1 diabetes.

How much do you know about the diabetic diet?

Patients with type 2 diabetes generally are put on a 1,500 to 1,800 calorie diet per day to promote weight loss and then the maintenance of ideal body weight. However, this may vary depending on the person’s age, sex, activity level, current weight, and body style.

More obese individuals may need more calories initially until their weight is less. This is because it takes more calories to maintain a larger body, and a 1,600 calorie diet for them may promote weight loss that is too fast to be healthy.

Men have more muscle mass in general and therefore may require more calories. Muscle burns more calories per hour than fat. (Thus also one reason to regularly exercise and build up muscle!) Also, people whose activity level is low will have less daily caloric needs.

Generally, carbohydrates should make up about 50% of the daily calories (with the accepted range 40% to 60%). In general, lower carbohydrate intake is associated with lower sugar levels in the blood.

However, the benefits of this can be canceled out by the problems associated with a higher fat diet taken in to compensate for the lower amount of carbohydrates. This problem can be improved by substituting monounsaturated and polyunsaturated fats for saturated fats.

Most people with diabetes find that it is quite helpful to sit down with a dietitian or nutritionist for a consult about what is the best diet for them and how many daily calories they need. It is quite important for diabetics to understand the principles of carbohydrate counting and how to help control blood sugar levels through proper diet. Below are some general principles about the diabetic diet.

Diabetes Slideshows You May Like

  • Type 1 Diabetes Slideshow
  • Type 2 Diabetes Slideshow

Understanding Food Groups
There are 3 basic food groups: fats, proteins, and carbohydrates. The carbohydrates are the foods that can be broken down into sugar. It is essential to have all 3 food groups in your diet to have good nutrition.

1. Why Count Carbohydrates?
Carbohydrates make your blood glucose level go up. If you know how much carbohydrates you’ve eaten, you have a good idea what your blood glucose level is going to do. The more carbohydrates you eat, the higher your blood sugar will go up.

2. Which Foods Contain Carbohydrates?
Most of the carbohydrate we eat comes from 3 food groups: starch, fruit, and milk.

Vegetables also contain some carbohydrates, but foods in the meat and fat groups contain very little carbohydrates. Sugars may be added or may be naturally present (such as in fruits).

The nutrient term for sugars can also be identified by looking for -ose at the end of a word ( ie, glucose, fructose, and sucrose are all sugars). Look for these on food labels to help identify foods that contain sugar.

Below are some examples of the grams of carbohydrate contained in a sampling of common food products:



Carb grams



Carb grams

1 % fat milk

1 cup

Yogurt, fruited

1 cup

Bran Chex

2/3 cup

Yogurt, plain

1 cup

Frosted Flakes

3/4 cup

Raisin Bran

3/4 cup

Fruit juice

1/2 cup

White Bread/toast

1 slice


Cane Sugar

1 tsp.

Pancake syrup

2 Tbsp.


Low-fat granola

1/2 cup

Sugar-free syrup

2 Tbsp.

To make things easy, many people begin to carbohydrate count by rounding the carbohydrate value of milk up to 15.

In other words, one serving of starch, fruit, or milk contains 15 grams carbohydrate or one carbohydrate serving. Three servings of vegetables also contain 15 grams. Each meal and snack will contain a certain total number of grams of carbohydrate.

For example: Each gram of carbohydrate provides 4 calories. A person with diabetes on a 1,600 calorie diet should get 50% of these calories from carbohydrates. This would be a total of 800 calories of carbohydrates (at 4 calories per gram) spread out over the day. At 15 grams per exchange, this would be about 13 exchanges of carbohydrates per day.

The amount of food you eat is closely related to blood sugar control. If you eat more food than is recommended on your meal plan, your blood sugar goes up. Although foods containing carbohydrates (carbs) have the most impact on blood sugars, the calories from all foods will affect blood sugar.

The only way you can tell if you are eating the right amount is to measure your foods carefully. Also, it is important to space your carbohydrates out throughout the day to avoid sugar “loading.” Measuring your blood sugar regularly also provides important feedback on how high your sugar went based on what you ate and your level of activity.

Where Do You Get Carbohydrate Information?
The “Nutrition Facts” label on most foods is the best way to get carbohydrate information, but not all foods have labels. Your local bookstore and library have books that list the carbohydrate in restaurant foods, fast foods, convenience foods and fresh foods. You will still need to weigh or measure the foods to know the amount of grams of carbohydrates present.

How Do You Count Carbohydrates?
Carbohydrates can be counted in number of grams or can be counted as exchanges. One carbohydrate exchange equals 15 grams of carbohydrates.

Free Foods
These are foods that you can eat without counting. A free food or drink is one that contains less than 20 calories and 5 grams or less of carbohydrates per serving. If your serving of a food contains more than 5 grams of carbohydrates, you should count it in your meal plan.

Examples of free foods:

  • Bouillon or broth
  • Carbonated or mineral water
  • Club soda
  • Coffee or tea
  • Diet soft drinks
  • Drink mixes, sugar-free
  • Tonic water, sugar free
  • Sugar-free hard candy
  • Sugar-free Jell-O
  • Sugar-free gum
  • Jam or jelly, light or low-sugar, 2 tsp
  • Sugar free syrup, 2 tsp

You should spread out free foods throughout the day and not eat them in one sitting.

Fitting Sugar in Your Meal Plan
It is commonly thought that people with diabetes should avoid all forms of sugar. Most people with diabetes can eat foods containing sugar as long as the total amount of carbohydrates (carbs) for that meal or snack is consistent.

Many research studies have shown that meals which contain sugar do not make the blood sugar rise higher than meals of equal carbohydrate levels which do not contain sugar. However, if the sugar-containing meal contains more carbs, the blood sugar levels will go up.

Can I Eat Cake and Not Worry About It?
No! A slice of white cake with chocolate icing (1/12 of a cake or 80 grams weight) will give you about 300 calories, 45 grams of carbs, and 12 grams of fat. That is 3 starch servings and over 2 fat servings.

Before you have a slice of cake, ask yourself the following questions: Will that small piece of cake be satisfying or will I still be hungry? How will it fit into my meal plan? Do I have 300 calories to “spend” on this? Are there other choices I could make which would contribute less fat?

A 1/12 slice of angel food cake has less than 1 gram of fat and only 30 carbs. This may be a better choice.

Controlling All Carbohydrates
It is important to realize that sugar is not the only carbohydrate that you have to “control.” The body will convert all carbohydrates to glucose, so eating extra servings of rice, pasta, bread, fruit, or other carbohydrate foods will make the blood sugar rise.

Just because something doesn’t have sugar in it doesn’t mean you can eat as much as you want. Your meal plan is designed so that the carbohydrate content of your meals remains as consistent as possible from day to day.

A Word of Caution
Although sugar does not cause the blood sugar to rise any higher than other carbohydrates, it should be eaten along with other healthy foods. If you choose to drink a 12-ounce can of a sugar-sweetened soft drink, that would use up about 45 grams of carba, and you wouldn’t have gotten any nutrition (protein, vitamins, or minerals). What a waste of calories!

High sugar foods are more concentrated in carb. Therefore the volume would be smaller than a low sugar food. High sugar foods might not be a good choice if they will just tempt you to eat more. If you would rather eat larger portions, select low sugar choices.

Look at the differences in portion size you get for equal amounts of carbohydrate in these cereals!


Frosted Flakes

Corn Flakes


Puffed Wheat

1/4 cup

1/3 cup

3/4 cup

1 cup

1 1/4 cup

In addition, many sugar-containing foods also contain a lot of fat. Foods such as cookies, pastries, ice cream and cakes should be avoided largely because of the fat content and because they don’t contribute much nutritional value. If you do want a “sweet,” make a low-fat choice, such as low-fat frozen yogurt, gingersnaps, fig bars, or graham crackers and substitute it for other carbohydrates on your meal plan.

Updated on: 04/02/19 Continue Reading Red Wine with Dinner? A New Study Says Yes, You Can

Low Carb vs. High Carb – My Surprising 24-day Diabetes Diet Battle

By Adam Brown

Twitter summary: What I learned from doubling my carb intake: the same average blood sugar, but four times as much hypoglycemia, more work, stress, & danger.

As a teenager, I ate a high carb diet that included lots of Goldfish crackers, white sandwich bread, pasta, and white potatoes. It was tasty, but it put my blood sugars on a wild roller coaster every single day. Things turned around in college when I learned about nutrition, got on CGM, and spent time with health conscious friends. I soon realized that eating less than 30 grams of carbs at one time was a complete gamechanger. I’ve stuck with that approach ever since.

But is this lower carb method actually better for my blood sugars, or have I just been fooling myself? To find out, I took on a somewhat terrifying self-tracking experiment:

  • 12 days of my usual, lower-carb diet, which averaged 146 grams of carbs per day (21% of daily calories). My carbs were primarily from nuts, seeds, vegetables, and a bit of fruit.

  • 12 days of a higher-carb, high whole-grain diet, which averaged 313 grams of carbs per day (43% of my daily calories). My sources of carbs were NOT junk food: plain oatmeal, whole wheat bread, quinoa, wild rice, and fruit.

Neither of these was unrealistic. My lower-carb diet was nowhere near Atkins level (20 grams per day), and the higher-carb diet was consistent with the “average” 45% carb diet in people with diabetes (according to ADA).

Even though this was a one-person (n=1) experiment, I wanted to be as scientific and fair as possible: eating whole, unprocessed foods in both periods; counting and tracking every single gram of carbohydrate (LoseIt! app); wearing CGM 24/7 and downloading the glucose data to document what happened (Dexcom G5 and Clarity); taking insulin before meals (5-15 minutes prior) and correcting when blood sugars went out of range; and keeping total calories and my high level of activity as consistent as possible (Fitbit).

Before starting, I assumed:

  • Low-carb eating = lower average blood sugar, much more hypoglycemia.

  • High-carb eating = higher average blood sugar, less hypoglycemia, way more fun.

How wrong I was!

To my utter surprise, both diets resulted in the same average glucose and estimated A1c. But there were major tradeoffs:

  • The higher-carb, whole-grain diet caused four times as much hypoglycemia, an extra 72 minutes per day spent high, and required 34% more insulin. (A less healthy high-carb diet would have been far worse.)

  • Doubling my daily carbs also added much more effort and produced far more feelings of exhaustion and diabetes failure. It was not fun at all, and the added roller coaster, or glycemic variation, from all the extra carbs made it more dangerous.

I would summarize it like this: high-carb eating felt like highway driving from Los Angeles to San Francisco, alternating between 120 mph and 10 mph. Low-carb eating felt more like driving between 55 and 75 mph. The final averages were the same (65 mph), but the experience was far different in terms of safety and effort.

This article details the results from this experiment, starting with the glucose and insulin data. The key part is the Lessons Learned section, where I’ve distilled my eight biggest takeaways. In the appendix are photos of the meals I ate and activity data. A follow-up article posted here answers reader questions sent via email or on Twitter. And if you find this article useful, check out my upcoming book, Bright Spots & Landmines!

This is far from a perfect experiment, and I recognize it has many limitations. The goal was to change my diet, to honestly document what happened (with real data from my devices), and to share what I learned. A lower-carb approach requires some tradeoffs (convenience, variety, time) that may not be worth it for everyone. But I hope this article sheds light on why lower carb seems to work for my diabetes, and more broadly, why we must move beyond A1c alone in describing glucose control.


Glucose Profiles

The plots below show my daily glucose profiles averaged over 12 days of high-carb and 12 days of low-carb eating. The black line shows the average at that time point, while the colored bars indicate the range of values at that time (yellow=high, gray = in range, red = low).

Can you guess which is high carb and which is low carb?

Observations: Low Carb

– Very consistent average throughout the day with no major spikes (black line).

– The bars are short and almost completely gray, meaning the vast majority of glucose values fell in the tight zone of 70-150 mg/dl.

– No obvious periods of serious highs or lows, consistent with my glucose data in the months prior to this experiment.

Observations: High Carb

– The black average line is more spikey, indicating more variability

– The bars at most time points are longer (wider range of values at one time), and there are more highs (yellow bars) and a few more lows (red bars).

– Trouble in early morning (highs), after breakfast (highs), late afternoon (lows), after dinner (highs), midnight (lows), and 1 AM-5 AM (steadily rising glucose).

Average Glucose, A1c, Time-in-Range

The different profiles above resulted in a near-identical average glucose and the same estimated A1c (low carb on left):

How is this possible? Averages can be misleading! Here are the time-in-range results, where things start to get interesting (low-carb on left):

To achieve the same average blood sugar on the high-carb diet, I experienced more than four times as much hypoglycemia (less than 70 mg/dl): 97 minutes vs. 22 minutes per day. I also had 72 extra minutes per day above 160 mg/dl during the high-carb period. Those trends mostly cancelled out, resulting in a similar average but far different blood sugar profiles.


I needed 34% more insulin on the high-carb diet, as my bolus insulin doubled to cover the additional carbs. I did not change my daily basal insulin (22 units) between the periods.

Low Carb

High Carb

Total Daily Dose

34 units

45 units


12 units
22 units

23 units
22 units

Lessons Learned

1. Average glucose and estimated A1c did not capture the vast difference in variability or hypoglycemia between the two phases. Look at the two plots below – the one on the left is from a low-carb day, while the one on the right was from a high-carb day. I chose these two days because they had near-identical average glucose levels: 123 mg/dl (low carb) vs. 121 mg/dl (high carb). But the diabetes experience of those days was FAR different.

Every day of high-carb eating also brought the dreaded double arrow trend on my CGM: glucose rising or falling at more than 3 mg/dl per minute. For example, a -100 mg/dl blood sugar change in 25 minutes. Those scary drops were like riding a roller coaster day after day. By contrast, low carb eating rarely resulted in more than a 1 mg/dl per minute change (-25 mg/dl in 25 minutes).

2. I experienced four times as much hypoglycemia on the high-carb diet. In my effort to treat highs, I had to accept more lows. This tradeoff between high and low blood sugars is what made high-carb eating a tightrope walk every day. I could have been less aggressive, but that would have caused longer and larger spikes in glucose. Low-carb eating made it easier to spend more time-in-range because there were fewer spikes and drops to deal with – instead of a tightrope, it was more of an open sidewalk.

3. Insulin is a dangerous drug, and doubling my carbs required 34% more every day. Large-carb meals also required two to five times more insulin in a single dose. My typical lower-carb meals needed one or two units at a time to cover vegetables, nuts, protein, and a bit of fruit – all raise glucose in small increments (+20 to +60 mg/dl) over a couple hours. By contrast, higher carb meals – even whole grains – often required five- and eight-unit boluses. Insulin has been called the second most dangerous drug (after the blood thinner warfarin), and insulin errors cause more than 97,000 hypoglycemia hospitalizations each year. I see value in taking smaller doses.

4. Feelings of stress and failure skyrocketed on the higher-carb diet. All the extra work and planning was exhausting! While a lower-carb diet generally lets me put diabetes in the background, a higher carb diet requires constant vigilance, measuring, worrying, reacting to CGM alarms, and pre-planning. My twelve days of large-carb meals were tiring and mentally taxing – I felt like I was getting it wrong all the time. Here are some of the differences in effort:

Low Carb Experience

High Carb Experience

Little carb counting. Flat one- or two-unit boluses for most meals and snacks

Constant carb counting, measuring and entering into bolus calculator. Highly variable amounts of insulin.

Take insulin at meal start, after, or not at all.

Critical to take insulin before meals

Easier to track boluses – one or two unit boluses stop lowering blood glucose in ~2 hours

Harder to track boluses – large doses (5+ units) can still be lowering glucose at 4+ hours

Smaller activity impact: boluses are small and not significantly accelerated from any type of exercise. Stable blood sugar makes activity easier.

Larger activity impact: big boluses are dramatically accelerated from light activities like walking. Variable blood sugar makes activity more challenging.

5. Higher-carb eating put more pressure on accurate and precise estimates (meal size, needed insulin, impact of activity), and penalized me harder for getting it wrong. As a hypothetical: if I’m about to take 10 units of insulin, but my estimate is 30% too high (the meal is actually 70 grams of carbs, not 100 grams), that’s a three-unit overdose. For me, that translates to a massive 105 mg/dl difference in blood sugar: 100 vs. 205 mg/dl, or even more dangerous, 45 vs. 150 mg/dl. Compare that to a meal with 20 g of carbs requiring two units of insulin – a 20% error = 0.4 units, or just a 14 mg/dl difference (glucose meter errors alone can be larger than that!). A lower-carb diet put much less pressure on having accurate estimates. I’m a big fan of reducing diabetes math!

6. High-carb meals were most challenging at breakfast. Look at the pictures below showing my three worst morning (7 am to noon) blood sugar curves for the 12 days of low carb (left) vs. 12 days of high carb (right). Low-carb meals were not perfect, but the post-breakfast highs were so much faster, higher, and longer after high-carb meals. As anyone with diabetes knows, breakfast makes a huge difference for getting a day of blood sugars started off right.

Low Carb vs. High Carb – Worst Mornings

7. It was a harder to remember to eat vegetables on the higher-carb diet. When meals contained 60 grams of carbs or more, it was easy to just eat a sandwich and a piece of fruit, or chicken and a side of rice – those meals felt “complete” as I was making them. On the low-carb diet, vegetables automatically filled the side-dish spot, and the meal didn’t feel “complete” unless some veggies were on the plate (a single piece of chicken is just not enough food!). My higher carb meals were less likely to include vegetables, since the reminder to include them was not as apparent.

8. Eating a higher-carb diet without checking glucose often or wearing CGM would be like driving a racecar at 150 mph blindfolded. For all the reasons listed above, checking blood glucose often (6+ times per day) or wearing CGM seems essential on a higher-carb diet – it allows for corrections after the inevitable turbulence of post-meal glucose spikes, large insulin doses, incorrect estimates, and hypoglycemia. I’m fortunate to have access to CGM, and I recognize this is not possible for everybody with diabetes. But for those who choose to eat high carb, checking glucose often is critical.

Concluding Thoughts

I’m leaving this experiment with an even better understanding of why lower-carb eating works for me. And as I’ve discussed in previous columns (and show below) there is still great variety and taste to be found in a lower-carb diet.

I do not believe there is a single diet for all people with diabetes – we all come from different circumstances, and what works for me may not be worth it for many others. I just know that my blood sugars were completely out of control as a teenager, and they are much more in control now. The biggest factor in that change was eating fewer carbs at each meal.

What works for you?


A follow-up piece answers the questions and comments I received following publication. You can send others along here or on Twitter.

Appendix 1: Meal Pictures and Calorie Information

Low Carb Meals

Here are some pictures of the typical low-carb meals I ate during this experiment. I’ve described my low-carb diet in depth in a previous column. It’s a lot of nuts and seeds, vegetables, chicken, fish, and eggs. I do eat some fruit (mostly berries and apples), but not every day.

High Carb Meals

My high carb meals relied on whole foods: old fashioned plain oatmeal; whole wheat bread or bagels or tortillas; fruit (apples, pears, berries); brown and wild rice; quinoa; sweet potatoes; etc. I wanted to isolate the impact of higher carb intake, so keeping the food healthy was essential – adding junk food would have confounded the experiment. The one disaster “healthy” food I tried was granola – yikes does that spike blood sugar quickly.

Calorie Information

I averaged very similar calorie intake during the two periods – 2,727 calories on low carb vs. 2,872 calories on high carb. It wasn’t identical – this wasn’t a lab setting! – but it was extremely close given the length of this experiment, the real-world eating I was doing (including meals out), and my level of activity. The extra hypoglycemia on the high carb diet could easily explain my very slightly higher-calorie intake during those 12 days.

A Note on Insulin Changes

For comparison, I deliberately kept my basal insulin and food bolus settings consistent between the two phases. Educator Jen Block pointed out that my insulin settings might be optimized to cover the lower-carb meals I usually eat (higher in fat and protein). Over a longer period of time, I could have changed my insulin settings to fine-tune them for the higher-carb diet. It’s hard to know how much that would have improved the glucose results.

There’s also an experience component here – the higher-carb diet added meals I have less experience taking insulin for. Even though I was counting the carbs accurately (reading the nutrition labels and using LoseIt!), there is no substitute for experience. It’s possible that if I kept at the high carb diet for long enough, I would have improved.

On half the nights during the low-carb phase, I wore overnight closed-loop from midnight to 7am (an extension of a study we previously wrote about). There are four reasons why I don’t think it had a major influence on the results: (i) the real difference between high carb and low carb appeared during the day, where the two phases were directly comparable on basal insulin; (ii) the closed-loop system used my pre-programmed basal rates as a guide, and those did not change between the two phases; (iii) my average 7am blood sugar was nearly identical between low carb and high carb phases (132 mg/dl vs. 137 mg/dl); (iv) the range of blood sugars at 7am was very similar between low carb and high carb (97-152 mg/dl vs. 108-161 mg/dl).

Appendix 2: Activity

As measured by my Fitbit, I averaged 16,653 steps per day on the low-carb diet vs. 18,505 steps on the high-carb diet. For some, that seems like a large difference in average activity, but it really isn’t – 1,852 steps per day is the equivalent of a 15-minute walk (0.8 miles), shorter than my daily commute to work. And as you can see from the chart below (showing daily distance walked for the 24-day period), the average is roughly similar with a few outlier days. I had one very active day on October 17 (long bike ride), which accounted for half of the total activity difference between the two periods. It would have been ideal to have identical steps in both 12-day stretches, but the tradeoff would have been a less real-world experiment.

Both 12-day periods were more active than my average 14,929 steps per day this year. A possible explanation is travel – I barely had any during the 24-day experiment (by intention), which allowed me to be more active than in a typical 24-day stretch with more travel.

Carbohydrates are a great source of energy for your body, but they affect your blood sugar too. If you have diabetes, keep track of how many you eat with a few simple tricks.

Know your carbs. It’s a lot more than just pasta and bread. All starchy foods, sugars, fruit, milk, and yogurt are rich in carbs, too. Make sure you count them all, not just the obvious ones.

Put together a meal plan. Figure out the amount of carbs, protein, and fat you can eat at meals and snacks throughout the day to keep your blood sugar levels steady. Most adults with diabetes aim for 45-60 grams of carbs per meal and 15-20 grams per snack. That number may go up or down, depending on how active you are and the medicines you take, so check with your doctor or a registered dietitian.

Look at labels. They make counting carbs easy. Find the “Total Carbohydrate” number listed on a package’s “Nutrition Facts” panel. Then, check the serving size and confirm the amount you can eat. Repeat this step with other foods you plan to eat. When you add all the grams of carbs, the total should stay within your meal budget.

Starch, fruit, or milk = 15. Fresh foods don’t come with a label. You may have to guess the number of carbs they have. A good rule of thumb: Each serving of fruit, milk, or starch has about 15 grams. Vegetables don’t have a lot, so you can eat more of them. Two or three servings of veggies usually equal 15 grams of carbs.

Pay attention to portion sizes. The size of one serving depends on the type of food. For instance, one small (4-ounce) piece of fresh fruit, 1/3 cup of pasta or rice, and 1/2 cup of beans are each one serving. Buy a pocket guide that lists carb counts and portion sizes. Or download an app on your smartphone. Measuring cups and a food scale when you eat at home will help you be accurate.

How many carbs should you have to control diabetes?

Q: I have had diabetes for two years. I am 6’3” and weight 215 pounds (having lost almost 100 pounds in the past 15 years). I have never heard anyone tell me how many carbohydrates one should have to control their diabetes. I talked with my doctors, but they seem more comfortable prescribing medications than giving me specific dietary recommendations. Where can I find this information?
– David H.

Answer by: Gary Scheiner MS, CDE, Clinical Director of Integrated Diabetes Services

A: So glad to hear that you’ve managed to get your weight down! What a difference that can make for your health.

You raise a great question about the amount of carbs in your diet. Honestly, the nutrient composition of your diet needs to be individualized. Carbohydrate, protein and fat all play a significant role in overall health maintenance, but we tend to become more carb centric when we live with diabetes since carbs affect blood sugar so quickly. Unfortunately, this often means protein and fat content aren’t equally considered.

The breakdown of nutrients should be tailored to your personal lifestyle and preference, as well as how your blood sugar responds to different foods. Blood sugar checks give us an inside look at how the body responds when carbohydrates are eaten. By doing a bit of food and blood glucose analysis, one might find that a certain amount of carb works best and/or specific carb-containing foods work better than others. It should also be considered combining carbohydrate with various amounts of protein and fat can have different effects on post meal blood sugars.

Other key factors to consider when determining carb requirements include lifestyle (how physically active you are), current weight, and whether you want to gain/lose/hold steady. A good chart for estimating your needs can be found here:

How to determine how many carbs to eat

Once you have a rough idea of your total calorie requirements, then you can determine what percent should come from carbohydrates. For most people, carbohydrates make up 40-50% of the day’s total calories. This can be a bit lower if your blood sugar is very sensitive to small amounts of carb; a bit higher if you exercise a great deal. For example, if you need 2000 calories per day and want 40% of the calories to come from carbohydrate, you would take 40% of 2000 (800) and divide by 4 since there are 4 calories per gram of carbohydrate. This comes to 200g of carb per day. The other 1200 calories then need to broken down into fat and protein calories to provide a balance of nutrients.

The distribution of those carbohydrates through the day makes can have a major impact on blood glucose levels. Eating all (or most) of the day’s carbohydrates in one sitting would be less effective than spreading the carbs throughout the day. Distributing carbs throughout the day is also a better way to provide satiety and avoid intense hunger. Similarly, having all of your carbs in the form of simple sugar and refined flour is not as beneficial as having carbs that come from whole grains, fruits, vegetables, legumes and dairy products.

Confused? Don’t worry. Most people are!

That’s why there are thousands of Registered Dietitians (RDs) available to work with people with diabetes. Ideally, look for an RD who is also a Certified Diabetes Educator (CDE) so that they can work with you to optimize your blood sugar control while customizing your meal plan.

Diabetes: Counting Carbs if You Use Insulin

How do you count carbohydrate grams in your diet?

To count carb grams at a meal, you need to know how many carbs are in each type of food you eat. This includes all food, whether it is a slice of bread, a bowl of lettuce, or a spoonful of salad dressing. Most packaged foods have labels that tell you how many total carbs are in one serving. Carbohydrate guides can help too. You can get these from diabetes educators and the American Diabetes Association.

To find out how many carbs are in food that is not packaged, you will need to know standard portions of carbohydrate foods. Each serving size or standard portion has about 15 grams of carbs.

By using the number of grams of carbs in a meal, you can figure out how much insulin to take. This is based on your personal insulin-to-carbohydrate ratio.

For example: Your doctor may advise you to take 1 unit of rapid-acting insulin for every 10 to 15 grams of carbs you eat. So if your meal has 50 grams of carbs and your doctor says you need 1 unit of insulin for every 10 grams of carbs, you would need 5 units of insulin to keep your post-meal blood sugar from rising above your target level.

Your insulin-to-carbohydrate ratio may change over time. In some people it will change from one meal to the next. You might take 1 unit of insulin for every 10 grams of carbs for lunch but take 1 unit for every 15 grams at dinner.

Keep these tips in mind when counting carbs:

  • Portion control is important. If a package says it contains two servings and you eat the whole package, you need to double the number of grams of carbs listed for one serving.
  • Protein, fat, and fiber do not raise blood sugar very much. If you eat a lot of these nutrients in a meal, carbs will change to glucose more slowly than it would with a meal that has a small amount of protein, fat, and fiber.
  • Advanced carb counting takes into account the amount of fiber or sugar alcohols in a food. For example, if a food has 5 or more grams of fiber per serving, you can subtract half the amount of fiber from the total number of carb grams. A food that has 30 grams of carbs and 8 grams of fiber would be counted as 26 grams of carbs. If you use a rapid-acting insulin, you may want to consider sugar alcohols if there are more than 5 grams of them in the food. Divide the number of sugar alcohols in half. Then subtract that number from the total carb count.
  • Exercise affects blood sugar. It allows you to use less insulin than you would if you did not exercise. Keep in mind that timing makes a difference. If you exercise within 1 hour of a meal, your body may need less insulin for that meal than it would if you exercised 3 hours after the meal.

When you keep track of what you eat and you test your blood sugar after meals and exercise, you can figure out what effect protein, fat, fiber, and exercise have on the amount of insulin you need.

To count carbs and eat a balanced diet:

  • Talk with a registered dietitian. He or she can help you plan how many carbs to include in each meal and snack. This includes sweets.
  • Measure your food portions. You won’t always have to measure your food. But it may help when you are first learning what makes up a standard portion.
  • Count either grams or servings of carbs.
  • Eat standard portions of foods that have protein. Foods that have protein (such as beans, eggs, meat, and cheese) are a key part of a balanced diet.
  • Limit saturated fats. A balanced diet includes a limited amount of healthy fat. Talk with a registered dietitian about how much fat you need in your diet.

Know your daily amount

Your daily amount depends on several things—your weight, how active you are, what diabetes medicines you take, and what your goals are for your blood sugar levels. A registered dietitian or certified diabetes educator will help you plan how much carbohydrate to include in each meal and snack.

For most adults, a guideline for the daily amount of carbohydrate is:

  • 45 to 60 grams at each meal. That’s about the same as 3 to 4 carbohydrate servings.
  • 15 to 20 grams at each snack. That’s about the same as 1 carbohydrate serving.

Other helpful ideas

  • Read food labels for carb amounts. Be aware of the serving size on the package.
  • Check your blood sugar level. If you do this before and 1 hour after a meal, you will be able to see how the food you eat affects your blood sugar.
  • Record what you eat and your blood sugar results in a food record. You can review your food record each time you visit your registered dietitian or certified diabetes educator. And you can review it anytime you think your meal plan needs adjusting.
  • Get more help. The American Diabetes Association offers booklets to help people learn how to count carbs in their diet. These booklets can also teach you how to measure and weigh food and to read food labels. But you will still need to talk with a registered dietitian to make a plan that fits your needs.

About the author

Leave a Reply

Your email address will not be published. Required fields are marked *