I am highlighting a study published in Nature Metabolism that examines the impact of exercise on beta cell function during weight loss. Beta cells and their pivotal role in our metabolic health have long been an interest of mine. I actually first became interested in obesity medicine when I started researching the  impact of diet and weight loss surgery on beta cell function and regeneration. However, the role of exercise in this process has not been well studied. This study begins to bridge this knowledge gap. 

Why are Beta Cells important for our metabolic health? 

• Beta cells produce and send out insulin to manage carbohydrates (specifically glucose) post-meal.
• As our body becomes resistant to its own insulin (insulin resistance), it demands more of it. This puts undue pressure on these beta cells, which ramp up their production, leading to “beta burnout,” driving obesity and associated metabolic syndromes, such as type 2 diabetes. Chronic glucose exposure, alongside excess weight and in particular, visceral fat, is thought to play the leading role in making our cell less sensitive (i.e. more resistant) to insulin. This is why diet and weight loss has been a key focus point when trying to reverse or decrease insulin resistance. 
• I also believe that independent of higher sugar levels and visceral fat, beta cell dysfunction in modern society is linked to our processed food and environmental exposures (in particular to plastics). In other words, society started to  get sick well before it gained weight. 

Key Findings From the Study 

The study divided 82 people with newly diagnosed type 2 diabetes into four groups for 16 weeks: 

• Standard care
• Calorie restriction (25% reduction)
• Calorie restriction + exercise three times per week
• Calorie restriction + exercise six times per week

The key findings were 

• Diet + Exercise Impact: Individuals who combined calorie restriction with an exercise regimen showed superior improvements in beta-cell function than those relying solely on diet or standard care.
  • Increases in insulin sensitivity seem more influenced by exercise, while changes in insulin secretion are mainly driven by weight loss.
  • The authors make the great point that it appears that weight loss of at least 5% may slightly enhance beta-cell function, while a weight loss of 11% or more may be needed to maximize peripheral insulin sensitivity improvement in people with obesity.
• Exercise Volume and Weight Loss: There was only a limited effect of increasing exercise volume from three to six sessions weekly in the context of diet-induced weight loss. Doubling the exercise volume didn’t lead to additional weight loss, suggesting the combination of exercise and diet is crucial, rather than the sheer volume of exercise.
• VO2max and Exercise Dose: The increase in both absolute and relative VO2max was positively associated with exercise dose. This indicates a potential cardiovascular benefit even if weight loss plateaus.

What now? 

Weight loss, dietary changes, and exercise are central for beta function and combining them has an additive effect likely by improving both insulin sensitivity and secretion. So embracing a holistic strategy improves our metabolic health down to the level of the beta cell!  Perhaps if we called this the beta diet plan, it would get as much buzz as the next weight loss fad.