Imagine your body as a complex machine that needs fuel to run smoothly. Proteins, fats, and carbohydrates are like different types of fuel for this machine, and they all have varying impacts on your blood sugar levels.
Carbohydrates are the quick-burning fuel. When you eat foods rich in carbohydrates (like bread, pasta, or sugary snacks), your body breaks them down into sugar (glucose) very quickly. This causes a rapid spike in blood sugar levels, which can give you a burst of energy but may lead to a crash later on.
Think of proteins as the slow-burning fuel. They take longer to break down into sugar and enter your bloodstream, so they have a gentler impact on blood sugar. Eating protein-rich foods (like chicken, eggs, beans, or tofu) with carbohydrates can help stabilize your energy levels and keep blood sugar more steady.
Fats are like the reserve fuel tank. They have little to no direct impact on blood sugar levels because they don’t turn into glucose right away. Instead, they provide a more sustained source of energy and can help prevent blood sugar spikes when eaten with carbohydrates.
Managing your blood sugar involves understanding how different foods affect you. Let’s take a deeper dive into carbohydrates, proteins, and fats, look at the types of foods to prioritize, and how to strike the right balance to maintain stable blood sugar levels and promote overall well-being.
When digested, carbohydrates are broken down into glucose (sugar). Glucose is the main source of fuel the body uses to support daily activities and functions. Our body can also use protein and fat as fuel, but not as quickly and effectively as carbohydrates.
With diabetes, the body has trouble moving glucose into the cells that need it for energy. When we eat large portions of carbohydrate at meals or snacks, it can cause our blood sugar to rise too high after that meal. One way we can better manage diabetes is by being mindful about the amount of carbohydrates, especially refined or highly processed carbs, we eat at each meal or snack.
The goal is to avoid having too much carbohydrate at one time, while still giving our body enough to have the energy it needs.
Foods that contain carbohydrates:
Non-starchy vegetables like leafy greens, broccoli, and tomatoes do contain some carbohydrates, but are not considered high carbohydrate foods.
Carbohydrate needs vary from person to person based on their current weight and activity level, but general recommendations suggest we consume between 40-60% of our daily calories from carbohydrates. It’s also suggested that for those who need to lose weight, the 40% target level may be more appropriate.
Here are some guidelines for grams of carbohydrates per meal and per day, but you can always discuss with your Registered Dietitian to determine the best option for you.
Women – inactive or to lose weight
Women – active or to maintain weight
Men – inactive or to lose weight
Men – active or to maintain weight
For snacks, aim for 15-20 grams of carbohydrates.
Within the category of carbohydrates, you can find dietary fiber. Fiber is a crucial component of a healthy diet, and they’re found in plant foods. The US Dietary Guidelines recommend consuming 22-34 grams of fiber daily, depending on age and overall calorie needs. Unfortunately, many Americans only get about one third to one half of the recommended daily fiber intake, partly due to a diet heavy in processed foods (which tend to contain little to no fiber), and a low intake of whole fruits and vegetables.
Fiber plays a significant role in promoting our health in several ways:
To increase fiber, focus on increasing whole grains, fruits, and veggies in your diet. Aim to drink at least 6 to 8 cups (8 ounces each) of water or calorie-free fluids daily to support this increase in fiber and your overall health.
Protein can be converted into sugar (glucose) by the liver and used for energy. This process takes longer than the breakdown of carbohydrates into sugar.
When you include protein with a meal or snack, it may slow down the digestion of the carbohydrates that are also in that meal. This can help prevent blood sugar levels from rising quickly.
Foods that contain high amounts of protein:
Protein needs can vary depending on your current weight and activity level. Your doctor may also recommend higher or lower amounts of protein, depending on your recent lab work.
Generally, it’s recommended that adults get about 10-35% of their daily calories from protein.
Looking at it another way, the minimum amount of protein a person needs each day is 0.8 grams per kilogram of body weight. For a 150-pound person, this would be 56 grams of protein per day, while for a 200-pound person that would be 74 grams of protein per day.
For those trying to build muscle mass or lose weight, slightly higher amounts may be needed.
Including a healthy and whole-food protein source at your meals or snacks (think turkey or beans, not protein powder) is a great way to ensure you’re getting enough protein each day.
Our bodies need fat to function on a day-to-day basis. Most of our cells have a coating around them made of fat. In addition, fat transports certain important vitamins throughout our bodies.
The fat we eat does not directly impact our blood sugar levels. When fat is combined with carbohydrate in a meal, it may slow down the digestion of the carbohydrate portion of that meal. This may mean blood sugar levels rise more slowly or have a delayed spike.
Foods that contain fats:
Recommendations for total fat vary, but in general, 20-35% of your calories should come from fats. It’s important to note that fat is the most concentrated form of calories at 9 calories per gram or roughly 45 calories per teaspoon. This is over twice the calories per volume as carbohydrates and protein. This does not mean that they should be avoided, but that we should be mindful of portions.
Fats are also tricky, since not all fats are created equal! Some fats provide a lot of benefits, while others are more likely to have a negative impact on our health.
Certain types of fat are heart healthy, while other types can increase our insulin resistance (and increase our blood sugar) and increase our bad cholesterol (LDL), as well. But which is which?
Saturated fats are typically solid at room temperature and are found in animal products like meat, butter, and full-fat dairy.
High intake of saturated fats may increase insulin resistance over time, making it harder for your body to control blood sugar levels.
Consuming too much saturated fat can raise levels of LDL cholesterol (often called “bad” cholesterol) in your blood, which can increase the risk of heart disease.
The American Heart Association guidelines for saturated fats are to limit your daily amount to less than 6% of daily calories, which is roughly 13 grams per day in a 2,000-calorie diet.
Trans fats contribute to insulin resistance, raise LDL (bad) cholesterol, lower HDL (good) cholesterol, and increase the risk of heart disease.
Trans fats occur in very small amounts in nature – usually in animal fat found in meats and dairy. But our primary source is from artificial trans fats found in ultra-processed foods. These lab-made fats were originally created to make liquid oils into a solid at room temperature, like margarine.
While trans fats in foods have technically been banned, they can still be found in fried foods at restaurants or for shelf-stable fried foods. Ultra-processed food manufacturers found a loop-hole that allows for some trans fat in your food. The rule states that foods must have 0 grams of trans fat per serving, but nutrition labels are rounded. Companies can claim their foods have “0 grams of trans fats” if they contain less than 0.5 grams of trans fat per serving. A few servings of an ultra-processed food or consuming fried foods often can mean the unhealthy trans fats can add up quickly!
Be sure to check the ingredient list of your nutrition label for these hidden trans fat sources: partially hydrogenated oil, soybean oil, corn oil, canola oil, or cottonseed oil.
Monounsaturated fats are typically liquid at room temperature and are found in foods like olive oil, avocados, nuts such as almonds, hazelnuts, and pecans, and seeds such as pumpkin and sesame seeds.
Eating these fats may improve insulin sensitivity, making it easier to manage your blood sugar. Monounsaturated fats are considered “heart healthy” as eating them in place of saturated fat lowers your risk of heart disease.
Polyunsaturated fats are also liquid at room temperature and are found in foods like fish, nuts such as walnuts, and seeds such as flax. These types of fats are also considered “heart healthy” and good for overall health.
One type of polyunsaturated fat, known as omega-3 fatty acids, are particularly beneficial. Some studies suggest that omega-3 fats may improve insulin sensitivity, which can be helpful for people with diabetes or those at risk of it. Eating foods high in omega-3 fatty acids also helps reduce inflammation and can lower the risk of heart disease by improving cholesterol levels.
Omega-3 fatty acids are found in higher amounts in walnuts, flaxseed, chia seed, omega-3 eggs, and fatty fish like salmon, tuna, mackerel, and sardines.
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U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition.
Zelman, K. The Great Fat Debate: A Closer Look at the Controversy – Questioning the Validity of Age-Old Dietary Guidance. The American Dietetic Association. May 2011. Volume 111: p655-658.
as of September 2023. Kelsea is a Registered Dietitian with her Masters degree in Nutrition from Bastyr University.
Always be sure to reach out to your healthcare team when making changes to your diet or lifestyle. There are certain conditions and medications that need to be considered.