Protein and Diabetes: What You Need to Know

By Constance Brown-Riggs

What is protein, how much protein should you eat, and what are the best sources of protein for people with diabetes?

In conversations about diabetes and meal planning, carbohydrates tend to take center stage. But protein also has a significant role to play in your health and wellbeing. Your organs, muscles, nervous system, blood vessels, and skeleton are all made of, and dependent on, protein. We’re here to break it all down: What protein is, why it’s important, how much you should be getting every day, the best sources of protein, and what the science says for people with diabetes.

What is protein?

Protein is an essential nutrient that is found in every cell in our bodies and in our blood stream. Our bodies use protein for growth, maintenance, energy, and chemical reactions – our muscles are made of protein; protein builds and maintains our bones, hair, nails, and skin; protein helps to support our immune system; and protein is used to make hormones, like insulin and glucagon. Protein is made up of building blocks called amino acids. There are 20 different types of amino acids; nine are considered essential because the body can't make them on its own. Each amino acid has a different, but vital, role to play in the body.

The protein you eat is classified as either complete or incomplete based on whether it contains all nine essential amino acids. Proteins from eggs, meat, fish, poultry, cheese, and milk are complete proteins. They contain all of the essential amino acids. Most plant proteins, such as nuts, seeds, beans, and grains, are incomplete. They do not have all the essential amino acids. Soy protein is the exception; it is a plant protein that provides all nine essential amino acids. You should eat a variety of proteins every day to make sure you get all of the amino acids your body needs, particularly if you are a vegetarian. 

Like carbohydrate, protein provides energy for the body; each gram of protein contains four calories. However, protein is not the body's preferred energy source. The body likes to use protein primarily to repair body tissue. 

How much protein do you need?

How much protein you need depends on your age, sex, health, and physical activity. On average, people with diabetes eat about the same amount of protein as the general public, which is 15-20% of their daily calories (typically 1-1.5 grams of protein per kilogram of body weight per day). The American Diabetes Association (ADA) does not recommend a specific amount of protein, but if you currently get less than 15-20% of your calories from protein, this is a good range to aim for. If you eat 2,000 calories per day, then about 300-400 of those calories would come from protein, which is about 75-100 grams of protein.

If you don’t keep track of your daily total calories, you can use the kilogram formula above to make sure you are getting enough protein. First, divide your weight in pounds by 2.2. If you weigh 170 pounds, that is equal to 77 kilograms (rounded off). That number is also the minimum number of grams of protein recommended for you. Then, multiply 77 by 1.5, and you get a maximum number of 116 grams of protein per day. For instance:

• A 170-pound person would eat about 77-116 grams of protein each day.

• A 200-pound person would eat about 90-136 grams of protein each day.

What are the best sources of protein?

Protein-rich food sources provide a variety of nutrients, including B vitamins (niacin, thiamin, riboflavin, and B6), vitamin E, iron, zinc, and magnesium, to keep your body functioning well. 

There are many sources of dietary protein, including:

• Poultry (chicken or turkey)

• Fish and seafood 

• Eggs

• Dairy (milk, cheese, yogurt) 

• Red meat (beef, pork, lamb, etc.)

• Plant proteins such as nuts, seeds, soy, and beans. 

Nature often packages proteins along with fat (e.g., cheese, steak, nuts) – be aware that this can add calories. There is also a small amount of protein in some cereals (like oats) and even rice, but these whole grains come with fast-acting carbs. Also watch out for overly processed protein foods and proteins with added sugar (such as protein snack bars, protein powders, and sweetened yogurt). 

Affordable sources of protein include canned fish, Greek yogurt, dried or canned beans, peanut butter, and ground turkey.

Will eating too much protein damage your kidneys?

You might have heard – or even been told –­ that people with diabetes should limit protein intake. The truth is, if you have full kidney function, it is not necessary to restrict protein. Keeping your glucose levels and blood pressure within your target range is the best way to prevent kidney damage.

What about people with diabetes and kidney disease? In the early days of diabetes care, people with diabetes and chronic kidney disease were advised to follow a low protein diet. We now know reducing protein intake in individuals with mild kidney disease does not change kidney disease progression. In fact, a low-protein diet may lead to malnutrition. Simply put, such a diet may do more harm than good. If you have kidney disease and diabetes, ask your healthcare professional how much protein they recommend that you eat.    

Do meals high in protein require extra insulin?

When you eat carbohydrates in combination with protein (or fat), it can take longer for your body to convert the carbs into glucose. This can be a good thing with snacks, but for larger meals the effect is hard to predict – it depends on the type and amount of carbs and the relative amount of protein and fat in the meal. The classic example is pizza, as you get lots of carbs from the crust alongside protein and fat from the cheese and toppings. You will see glucose levels rise after eating pizza, but glucose could remain elevated for up to six hours, depending on how much you ate.

For people taking mealtime insulin, the effect of the protein (or fat) has to be taken into consideration. For big meals, some people “stretch out” the dose by taking less insulin around the time of the meal and then a correction bolus later, or they use their insulin pump to deliver a dual or extended bolus. 

In this way, large “mixed meals” (such as holiday meals or restaurant food) can pose a real problem, because taking too much insulin too early might cause you to go low. That’s why it’s a great idea to test your blood sugar a few hours after the meal or, if it is available to you, use a continuous glucose monitor (CGM) to stay on top of your glucose levels.

Can you eat fruit for a snack without also eating protein?

Yes, you can eat fruit for a snack. Eating something with protein and fat when eating fruit is often suggested to keep you full and to help prevent a spike in glucose levels. A typical example is apple slices with peanut butter – or any nut butter, spread on top of each slice. Eating a handful of nuts with a piece of fruit can have the same effect. Everyone’s body is different, so remember to check glucose levels to determine what works best for you.

Should you use carbohydrate and protein to treat hypoglycemia?

The ADA recommends pure glucose as the preferred treatment for hypoglycemia (low blood sugar), although any form of carbohydrate that contains glucose will raise your glucose level. Carbohydrate sources high in protein should not be used to treat or prevent hypoglycemia. 

To learn more about nutrition and diabetes, click here. If you’re looking for protein-rich meal and snack ideas, check out Catherine Newman’s recipes.

About Constance

Constance Brown-Riggs, MSEd, RDN, CDCES, CDN, is a national speaker and author of the award-winning Diabetes Guide to Enjoying Foods of the World, a convenient guide to help people with diabetes enjoy all the flavors of the world while still following a healthy meal plan, and The African American Guide to Living Well with Diabetes. Learn more about Constance and follow her on Instagram and Facebook.