It’s common knowledge that insulin is a hormone that regulates blood sugar levels, impacting appetite and energy. What you might not know is that how sensitive your body is to insulin predicts how much body fat you will lose from different kinds of diets.
For example, people who have higher insulin levels and greater insulin resistance will lose more body fat from a low-carb diet than a low-fat diet because carbohydrate restriction restores the cell’s sensitivity to insulin. On the other hand, people who are more insulin sensitive can get results even if they eat a higher proportion of their calories from carbohydrates.
Why is insulin sensitivity so important?
It all has to do with how the pancreas releases insulin into the blood to regulate blood sugar. Scientists have identified two distinct phases of insulin secretion:
Phase 1 insulin release involves the secretion of insulin that is already made and stored within the beta cells of the pancreas. The first phase occurs quickly, within the first few minutes after you eat and blood glucose levels rise. Phase 1 lasts about 10 to 15 minutes.
Phase 2 is a slower, more prolonged release of insulin that requires the pancreas to make new insulin. It takes time to get going and cannot be relied on for effective glucose management if phase 1 is diminished.
In people without diabetes who have good glucose control, phase 1 enables them to eat foods high in simple carbs such as cake, bread, or sugar without glucose rising too much. The stored insulin is released quickly and able to manage glucose levels to avoid large glucose spikes.
Phase 1 is extremely important for effective glucose metabolism and when it is disrupted, the stage is set for impaired glucose tolerance and Type 2 diabetes. Fat gain, problems with appetite regulation, low energy, and inflammation are all side effects of poor glucose tolerance and problems with phase 1 insulin release.
When phase 1 insulin secretion is diminished, blood glucose levels tend to spike after meals. The pancreas compensates for this large elevation by increasing phase 2 insulin release, secreting new insulin, and often overshooting the amount of insulin necessary to bring glucose levels back to normal. The result is a rapid and precipitous drop in glucose levels. The high insulin also has harmful physiological effects, damaging beta cells in the pancreas and impairing their ability to function properly.
Over time, cells in the body aren’t able to utilize glucose efficiently and they become resistant to insulin. Both phase 1 and 2 are necessary for preventing type 2 diabetes, but many scientists believe it’s worth focusing on phase 1 insulin release for successful blood sugar management.
A clinical test called the GlycoMark test is used to measure how well phase 1 insulin is working and identify if you have high glycemic variability in response to meals—simply, large peaks and valleys in blood sugar levels. Why does this matter?
Poorly functioning phase 1 insulin release is a predictor of diabetes.
It’s also a predictor of cardiovascular disease. The biggest physiological correlation between heart attacks is with high insulin levels, especially spikes in insulin. This means that someone with an average post-meal blood sugar of 150 will be at greater risk of disease if they have large insulin spikes after meals (due to poorly working phase 1 insulin release) than someone with an average post-meal blood sugar of 175 who doesn’t experience the same spikes and valleys.
What can you do to improve your phase 1 insulin release?
The first step is to get a blood glucose meter to test your blood sugar at home before and after eating. The smaller the increase in glucose from pre- to post-meal, the better your phase 1 insulin release and glucose management in general.
Dietary steps you can take include the following:
- Eat fibrous (especially leafy green) vegetables at every meal
- Avoid foods with added sugar
- Avoid refined carbs (sweets, bread, pasta, crackers, chips, etc.)
- Eat high-quality protein at every meal (eggs, fish, poultry, meat, beans, nuts, dairy)
- Include healthy fat (nuts, olive oil, dairy foods, avocado) to slow digestion (leading to a more moderate elevation in blood sugar) and manage appetite
Get your exercise in: Performing a regular strength training program will help increase muscle, raising the number of insulin receptor sites. Doing intervals or endurance exercise will sensitize your cells to insulin and increase your body’s glucose needs.
Finally, avoid being sedentary by taking frequent walks and being as active as possible in daily life.
McClain, A., et al. Adherence to a Low-Fat versus Low-Carbohydrate Diet Differs by Insulin Resistance Status. Diabetes, Obesity, and Metabolism. 2013. 15(1): 87–90.