Losing weight isn't just about reducing your calorie intake. It's also about changing the kinds of foods you eat — and that, in turn, can alter your insulin levels.
You may have heard that eating fewer carbohydrates is important to a healthy diet. That's not just because carb-rich foods such as breads, pastas and desserts are often high in calories. Carbohydrates have a complex effect on the body's blood sugar and insulin levels — and understanding that carb-glucose-insulin link can be key to adopting a successful weight-loss strategy.
Carbs, Blood Sugar and Insulin
The body breaks down carbohydrates into a type of sugar called glucose. Glucose, also known as blood sugar, is the body's primary source of energy. It circulates in the bloodstream to reach and fuel all the organs of the body.
Certain carbohydrates (such as sodas, juices and candies) are known as "simple carbohydrates"; they're converted into glucose very quickly, temporarily raising blood sugar levels beyond a healthy level. But the body has a method to correct this.
Insulin, a hormone secreted by the pancreas, moves glucose out of the bloodstream and into the cells, thereby lowering blood sugar levels. When blood sugar levels are high, the body releases more insulin. However, high levels of insulin also prompt the body to store extra glucose as fat instead of removing it through urine, according to the Mayo Clinic.
Diabetes and Insulin
Controlling blood sugar levels through diet and exercise is usually the first step in managing prediabetes and type 2 diabetes, according to the Cleveland Clinic. These conditions occur when the body becomes insulin-resistant, meaning the cells are less sensitive to the insulin's blood-sugar-regulating effects. This results in high blood sugar, which in turn triggers the pancreas to produce even more insulin. Eventually, the pancreas can't keep up with the demand, leading to chronic high blood sugar.
People with prediabetes and type 2 diabetes can reduce blood sugar levels by following a carbohydrate-controlled diet. Lower blood sugar means the body needs less insulin. Low-carb diets can even increase the body's insulin sensitivity, according to Diabetes.co.uk.
6 Steps for Healthier Blood Sugar Levels
1. Limit Simple and Refined Carbs
The first line of defense in reducing insulin levels is to limit or avoid foods that cause your blood sugar to spike in the first place. This includes the simple-carbohydrate foods mentioned earlier, which the body converts into glucose very quickly.
It's also wise to limit or avoid refined carbs, such as white bread and white rice. Unlike healthy whole grains, these foods have been stripped of most of their fiber, so the body converts them into glucose quickly as well, causing blood sugars — and insulin levels — to rise accordingly, per the Harvard T.H. Chan School of Public Health.
If you want to balance your blood sugar levels, it's a good idea to limit or avoid the following foods, according to the American Diabetes Association (ADA).
- White bread
- White rice
- Candies and baked goods
- Sweetened breakfast cereals
- Flavored coffee drinks
- Sweeteners like honey, agave or maple syrup
- Sodas, fruit juices and energy drinks
2. Get Complex
Add whole grains to your diet. Unlike processed grains, whole grains have retained the bran and germ — the parts of the grain that account for the bulk of their fiber. Fiber makes these carbs, known as complex carbs, break down more slowly, resulting in steadier releases of glucose and insulin, per the Harvard T.H. Chan School of Public Health. Fiber-rich foods also contribute to a feeling of fullness, meaning you'll likely eat less overall — a cornerstone of any weight-loss strategy.
Per the ADA, smart carb choices include:
- Whole-grain breads
- Brown rice and wild rice
- Bulgur wheat
- Legumes such as black beans, lentils and chickpeas
3. Make a Meal of It
Exchanging simple carbs for complex carbs is a great step toward keeping blood sugars stable. Another good strategy is to eat carbs as part of a meal that also includes fats and lean proteins such as poultry, tofu, eggs, nuts or low-fat dairy, instead of just eating carbs on their own.
The addition of fats and proteins will keep your body from converting the carbs into glucose too quickly, therefore preventing your blood sugar levels from spiking. Furthermore, a small July 2015 study published in Diabetes Care reaffirmed the findings of older studies, which found that eating veggies and proteins before carbs had the greatest impact on preventing high blood sugar and insulin levels after eating.
4. Eat Your Veggies
Vegetables are an important part of everyone's diet. But they are especially important for people with prediabetes or diabetes. According to Heidi Karner, RDN, LDN, a nutrition and diabetes educator at Boston's Joslin Diabetes Center, the fiber found in vegetables is a key factor in blood sugar and insulin control. "The insoluble fiber that's in a lot of nonstarchy vegetables such as broccoli, asparagus and cauliflower helps slow the absorption of glucose into your bloodstream, and can help prevent blood-sugar spikes," she says.
She also points out that fibrous vegetables are low in calories while being very filling, which can help reduce overall calorie intake. Because of all of these benefits, Karner says, the Joslin Diabetes Center urges people with insulin resistance to fill half of each dinner plate with nonstarchy vegetables. This is in line with the 2015-2020 Dietary Guidelines for Americans, published by the U.S. Department of Agriculture, which recommends filling half your plate with fruits and veggies.
5. Regulate Your Carbs
Karner recommends eating the same amount of carbs each day, at regular intervals. "To keep your blood sugar [and insulin] levels under better control, space out your carbohydrates throughout the day," she advises. By not consuming your daily carbs in one or two sittings, you'll keep your blood sugar from suddenly spiking.
6. Get Moving
Exercise is a critical component of weight loss and blood sugar stabilization, even if you follow an insulin-resistance diet. Why? Because exercise doesn't just burn calories — it also makes the body more sensitive to insulin, according to a study published in the May 2012 issue of Medicine & Science in Sports & Exercise.
To maintain healthy blood sugar and insulin levels — and general fitness — the ADA recommends at least 150 minutes of aerobic activity every week, or about 30 minutes most days.
Recommended exercises include:
Is This an Emergency?
- Mayo Clinic: "Insulin and weight gain: Keep the pounds off"
- Medicine & Science in Sports & Exercise: "Exercise Dose and Insulin Sensitivity: Relevance for Diabetes Prevention"
- U.S. National Library of Medicine: "Simple carbohydrates"
- USDA: 2015-2020 Dietary Guidelines
- American Diabetes Association: Physical Activity/Exercise and Diabetes: 2016 Position Statement
- Cleveland Clinic: "Do You Worry About Getting Insulin Shots for Type 2 Diabetes?"
- Diabetes.co.uk: "How Does Low Carb Work?"
- Harvard T.H. Chan School of Public Health: "Carbohydrates and Blood Sugar"
- American Diabetes Association: "What Can I Eat?"
- Diabetes Care: "Food Order Has a Significant Impact on Postprandial Glucose and Insulin Levels"
- Key Points from the Updated Guidelines on Exercise and Diabetes
- Exercise Dose and Insulin Sensitivity: Relevance for Diabetes Prevention
- Insulin and weight gain: Keep the pounds off