Advice for staying healthy often focuses on regular exercise and limiting fatty foods. Physical activity helps lose excess weight, build muscles and strengthen the heart. It also improves the body’s ability to absorb oxygen and produce energy. It is considered one of the most reliable indicators of long-term health and longevity.
However, people with high blood sugar levels often miss out on some of these benefits of exercise, especially the increased efficiency of the body’s use of oxygen. Elevated blood sugar levels increase your risk of heart and kidney disease. It can also interfere with your muscles’ ability to increase oxygen uptake during physical activity.
For those facing this challenge, new research suggests unexpected possibilities. Rather than reducing fat intake, increasing fat intake may help.
Ketogenic diet studies show improved exercise response
A study led by exercise medicine researcher Sarah Lessard and published February 25 in Nature Communications investigated how diet affects exercise responses. The research team found that mice fed a high-fat ketogenic diet showed a reduction in high blood sugar levels, also known as hyperglycemia. Their bodies also responded better to exercise.
“After a week on the ketogenic diet, their blood sugar levels were completely normal, as if they didn’t have diabetes at all,” said Lessard, an associate professor in the Fralin Biomedical Research Institute at the VTC Exercise Medicine Research Center. “Over time, this diet caused the mice to rebuild their muscles, increasing their oxidative power and making them more responsive to aerobic exercise.”
The ketogenic diet gets its name from ketosis, a metabolic state in which the body switches from using sugar as its primary fuel to burning fat. This diet relies on high-fat foods and severely restricts carbohydrates, which contrasts with the low-fat diet traditionally recommended by many health experts.
Potential health benefits of the ketogenic diet
Despite the controversy surrounding the keto diet, it is associated with health benefits for certain diseases such as epilepsy and Parkinson’s disease. Historically, it was also used to manage diabetes. Until the discovery of insulin in the 1920s, doctors sometimes relied on this approach to lower blood sugar levels.
Lessard’s previous research has shown that people with elevated blood sugar levels often have reduced exercise capacity. This led her to explore whether a ketogenic diet could help restore the body’s ability to adapt to exercise.
In this study, mice were fed a high-fat, low-carbohydrate diet and periodically ran on an exercise wheel. Over time, their muscles develop more slow-twitch fibers, which leads to greater endurance.
“Their bodies are using oxygen more efficiently, which is evidence of increased aerobic capacity,” Lessard said.
Why diet and exercise are the most effective
According to Lessard, exercise benefits nearly every tissue in the body, including fatty tissue. However, increasing evidence suggests that the greatest health improvements occur when diet and exercise are combined, rather than treated as separate strategies.
“What we really know from this study and others is that diet and exercise don’t just work in isolation,” said Lessard, who also holds a position in the Department of Human Food, Nutrition, and Kinesiology at Virginia Tech’s College of Agriculture and Life Sciences. “There are many compounding effects, so you can get the most benefit from exercise if you eat a healthy diet at the same time.”
Future research and practical dietary options
Lessard plans to expand the study to human participants to determine whether people experience the same improvements seen in mice.
She also points out that sticking to a ketogenic diet can be difficult. For many people, a less restrictive eating plan like the Mediterranean diet may be easier to maintain while maintaining healthy blood sugar levels. Rather than eliminating carbohydrates completely, this approach includes carbohydrates from whole foods such as fruits, vegetables, and whole grains.
“Our previous research shows that any strategy you and your doctor come up with to lower your blood sugar levels is likely to work,” she says.
