Science of Using CGMs for Weight Loss

Many foods that you eat can increase your glucose. Your body has a complex hormonal response to keep glucose relatively in a “normal” range. However, excess fat, insulin resistance, pre-diabetes, and other factors are associated with higher, longer glucose spikes.

People have unique glucose responses to food; scientists noted a “high variability in response to identical meals, suggesting that universal dietary recommendations may have limited utility.” This research supports the idea that each person can respond differently to food, food combinations, and the context in which the food was consumed.

Americans eat and drink more frequently than they did 30 years ago; this increases the number of times a day that blood glucose will rise and may indicate an overall increase in energy intake.

A low-GI and energy-restricted diet containing moderate amounts of carbohydrates may be more effective than a high-GI and low-fat diet at reducing body weight and controlling glucose and insulin metabolism.

When a group of overweight, healthy adults consumed a low-fat, high-carb breakfast, they experienced higher post-meal insulin, a more rapid rise and fall in peak glucose, and more hunger at 3-4 hours after the meal compared to a group that ate a high-fat, low-carb breakfast. The rise and fall in glucose (versus the total concentration of glucose) likely explained the earlier return of hunger in the low-fat, high-carb group.

Fluctuations of glucose throughout the day are normal to a certain degree, but small spikes and dips may influence behavior. A 2021 study of people under real-world conditions, wearing continuous glucose monitors, showed that lower glucose dips following a meal were predictive of eating sooner and eating more calories at that subsequent meal.

We investigated the effect of low and high glycemic load (GL) diets on satiety and whether satiety varied by body mass index (BMI), gender, and serum leptin. In summary, reducing GL, and/or increasing fiber, may be an effective way to lower calories consumed, improve energy balance, and ultimately reduce cancer risk.

Study participants with higher baseline insulin levels and inflammation showed decreased weight loss during a calorie-restricted diet—and were more prone to regaining weight lost after the diet.

Newly diagnosed patients with type 2 diabetes reported a 4% body weight loss over 6 months from avoiding high-glycemic foods, eating foods that don’t cause large glucose spikes, including physical activity, and monitoring glucose levels via fingerstick. Weight loss was not a focus in this study, but patients who followed the GEM paradigm (glycemic load, exercise, monitor glucose) showed that addressing high sugar intake led to weight loss.

Compared with an isocaloric low-GI meal, a high-GI meal decreased plasma glucose, increased hunger, and selectively stimulated brain regions associated with reward and craving in the late postprandial period, which is a time with special significance to eating behavior at the next meal.

This research supports a causal relationship between genetically determined glucose-stimulated insulin secretion and obesity. A lifetime of consumption of foods with a high-glycemic load promotes weight gain through the anabolic effects of increased insulin secretion.

Study participants followed the GEM paradigm using continuous glucose monitors instead of self-monitored glucose checks. Participants had an average 17-pound (7%) weight loss over 3 months, with significant reductions in BMI, blood pressure, and other health markers.

High-glycemic foods suppress leptin, a hormone that helps regulate energy balance by inhibiting hunger. Lower post-meal insulin and higher leptin levels suggest that low-glycemic meals instigate a metabolic response that encourages people to eat less.

Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.