- Regular exercise may have significant benefits when combined with diet-induced weight loss for people with overweight and prediabetes, according to new research.
- The study aimed to determine whether exercise provides benefits beyond weight loss achieved through diet alone.
- The study compared two groups: one followed a diet program and exercise training, while the other followed only the diet program.
- The results showed that the group that combined diet and exercise experienced twice as much improvement in insulin sensitivity, which is crucial for managing prediabetes, compared to the group that followed diet alone.
In a new study, scientists at the Center for Human Nutrition at Washington University School of Medicine, St. Louis, Missouri, looked at the effects of regular exercise combined with a diet program for overweight and prediabetic people.
The researchers measured how sensitive the participants’ bodies were to insulin, a hormone that regulates blood sugar.
The results showed that the group that changed both their diet and exercise habits had twice the improvement in insulin sensitivity compared to the group that changed only their diet.
This means their bodies could use insulin better to control their blood sugar levels.
The researchers also looked at certain genes in the participants’ muscles and found that the group that changed both diet and exercise had increased expression (activity) of genes involved in making new mitochondria – the energy factories in cells. – energy metabolism and the growth of new blood vessels.
These changes in gene activity indicate that exercise helps improve overall muscle function and health.
They found no significant differences between the two groups in certain markers in the blood related to inflammation or the levels of certain amino acids.
In addition, both groups showed similar changes in the composition of their gut bacteria, which may affect overall health.
The study is published in Nature Metabolism.
Dr. Sergio P Ramoa of Atrius Health, who was not involved in the study, spoke to Medical News Today and explained that “despite the growing focus and treatment of obesity and diabetes, diabetes-related mortality in the first 20 years of the 21st century.”
“The mindset of obesity treatment has changed, with a focus [on] treatment of obesity such as a chronic disease, such as hypertension or asthma. As social, educational and therapeutic mindsets change, significant progress has been made in weight loss treatment and weight maintenance.”
— dr. Sergio P. Ramoa
Dr. Romoa noted that “this article demonstrates why exercise remains a mainstay not only of weight management treatment, but of the overall health of the community.”
“Exercise should always be used in conjunction with pharmaceutical treatment for sustained lifestyle changes,” he said.
Kelsey Costa, a registered dietitian and health research specialist at the National Coalition on Healthcare (NCHC), who was also not involved in the study, agreed, telling MNT that “the study findings imply that combining exercise with a calorie-restricted diet may improve insulin sensitivity and metabolic health beyond the benefits achieved through diet-induced weight loss alone.”
“Given what we know about the barriers to exercise in obese people, it is essential to understand how effectively this combination of therapies can improve metabolic health,” Costa noted.
When a person has prediabetes, their blood glucose levels are consistently high, but not yet high enough to develop type 2 diabetes.
It serves as a warning sign of an increased risk of developing diabetes, but with lifestyle changes it can often be prevented or delayed.
Exercise improves insulin sensitivity
Dr. Romoa explained that “exercise improves insulin sensitivity through GLUT4, the main insulin-driven glucose transporter.”
“GLUT4 can be seen in muscle and fat tissue. Based on a person’s diabetes and obesity status, the number of these transporters changes. They are reduced in fat tissue but remain at normal levels in muscle tissue. This allows exercise to continue to improve glucose control. Fat tissue is no longer able to fully modulate blood glucose due to insulin resistance. Exercise will also upregulate GLUT4 levels in the body. All forms of exercise can improve glucose levels, including walking.”
— dr. Sergio P. Ramoa
Costa noted that, according to this study, “exercise improves insulin-stimulated glucose uptake, likely due to changes in skeletal muscle biology induced by exercise.”
“This includes an up-regulation of genes involved in mitochondrial energy metabolism and substrate oxidation and an improvement in mitochondrial content and function. Consequently, the diet plus exercise group experienced a more substantial increase in muscle insulin sensitivity,” explains Costa.
Past research shows that exercise is highly recommended as a primary treatment for type 2 diabetes.
Moderate to vigorous exercise for 150 minutes a week, combined with diet and behavior changes, can prevent, slow, or reverse the disease.
Various types of exercise, including aerobic exercise and resistance training, can control blood sugar levels. High-intensity interval training and small movements throughout the day are beneficial.
Timing exercise, such as exercise in the afternoon and exercise after a meal, may provide additional benefits.
Optimal exercise recommendations, taking into account individual factors, are still being studied, so working with healthcare professionals is essential for personalized diabetes management.
Costa stressed “the importance of integrating a calorie-restricted diet with exercise to improve metabolic health and physical function.”
“These results are essential for patients and healthcare providers as they help develop tailored approaches to weight management. This is particularly relevant given the widespread prevalence of obesity and associated risks,” she said.
“While the benefits of exercise are clear, barriers to physical activity within this target group often hinder its integration into weight loss programs. Those in the diet plus exercise cohort did 6 hours of resistance training and aerobic exercise per week. However, implementing this regimen in real world situations can be challenging depending on individual lifestyle, health status and available resources.”
– Kelsey Costa, MS, RDN
“Still,” said Costa, “the results of this study suggest that clinicians should consider ways to incorporate more structured exercise into weight loss protocols.”
“At the same time, public health initiatives need to determine ways to make exercise programs more accessible,” she said.
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