Scientists Reveal Why Bread Can Cause Weight Gain Without Overeating17 April 2026 ByDavid Nield (Photographer Basak Gurbuz Derman/Moment/Getty Images) New research in mice shows how eating bread can cause body weight and fat mass to increase, even though caloric intake stays at a similar level. The research, led by a team from Osaka Metropolitan University in Japan, highlights how carbohydrates can contribute to weight gain as well as excessive fat intake – which is what dietary advice tends to focus on. This isn't the first time nutritionists have talked about bread and carbohydrates and their contribution to weight gain, but there hasn't been much detailed research into the relationship – especially wheat flour – or into what might be happening at a metabolic level. The team discovered that eating more wheat bread was associated with reduced energy expenditure, pushing the metabolism towards a state where fat storage is prioritized, even when the calories in a diet stay at a similar level. The researchers analyzed the difference that bread in the diets of mice had on their weight (A) and fat tissue (B, C). (Matsumura et al., Mol. Nutr. Food Res., 2026) "These findings suggest that weight gain may not be due to wheat-specific effects, but rather to a strong preference for carbohydrates and the associated metabolic changes," says nutritionist Shigenobu Matsumura of Osaka Metropolitan University. The researchers set up experiments in which lab mice were given a choice between their normal, healthy cereal-based diet and either simple bread, baked wheat flour, or baked rice flour. The mice were then monitored to check their weight and how their bodies burned calories at rest and when active. Using blood samples, the study team also examined hormone, blood sugar, and metabolite levels in the animals, while post-experiment tissue analyses assessed gene expression in the liver. The experiments showed that the mice strongly preferred to switch from their standard diet to carbohydrate-heavy snacks, which then led to weight gain and more fat tissue in the mice, particularly in the males. Further analysis and follow-up tests suggested that these two key changes were being driven not by overeating or a lack of exercise, but by the foods themselves. In the wheat flour diet, fewer calories were being burned overall, while genes responsible for turning carbohydrates into fat were activated. Another follow-up test focusing on the wheat flour group showed that when the chow diet was restored, the weight gain stopped, and the metabolic shifts were reversed. "In the future, we hope this will serve as a scientific foundation for achieving a balance between 'taste' and 'health' in the fields of nutritional guidance, food education, and food development," says Matsumura. The findings are more evidence of how what we eat can cause changes in how our body processes food and burns the calories it contains. In the case of bread, it seems to slow down the body's metabolic engine. One limitation of the study is that it used mouse models, rather than human volunteers. While it's likely that similar processes are happening in people, it's not certain – so that's something future studies can pick up. The researchers also want to experiment with a broader selection of foods to identify what exactly it is about bread that causes this reaction. No diet study like this exists in isolation, of course. We know that a variety of other factors can also impact how our metabolism reacts to food and drink, including age and hormone-related changes. Related: There's a Surprising Link Between a Key Nutrient, Obesity, And Alzheimer's Risk Further research should help establish the role that wheat and bread can play in a diet and how the simple "calories in, calories out" rule isn't always straightforward. "Going forward, we plan to shift our research focus to humans to verify the extent to which the metabolic changes identified in this study apply to actual dietary habits," says Matsumura. "We also intend to investigate how factors such as whole grains, unrefined grains, and foods rich in dietary fiber, as well as their combinations with proteins and fats, food processing methods, and timing of consumption, affect metabolic responses to carbohydrate intake." The research has been published in Molecular Nutrition & Food Research. ARTICLE SOURCE: https://www.sciencealert.com/scientists-reveal-why-bread-can-cause-weight-gain-without-overeating
FDA Clears First Over-the-Counter Continuous Glucose Monitor
Today, the U.S. Food and Drug Administration cleared for marketing the first over-the-counter (OTC) continuous glucose monitor (CGM). The Dexcom Stelo Glucose Biosensor System is an integrated CGM (iCGM) intended for anyone 18 years and older who does not use insulin, such as individuals with diabetes treating their condition with oral medications, or those without diabetes who want to better understand how diet and exercise may impact blood sugar levels. Importantly, this system is not for individuals with problematic hypoglycemia (low blood sugar) as the system is not designed to alert the user to this potentially dangerous condition.
“CGMs can be a powerful tool to help monitor blood glucose. Today’s clearance expands access to these devices by allowing individuals to purchase a CGM without the involvement of a health care provider,” said Jeff Shuren, M.D., J.D., director of the FDA’s Center for Devices and Radiological Health. “Giving more individuals valuable information about their health, regardless of their access to a doctor or health insurance, is an important step forward in advancing health equity for U.S. patients.”
The Stelo Glucose Biosensor System uses a wearable sensor, paired with an application installed on a user’s smartphone or other smart device, to continuously measure, record, analyze and display glucose values in people 18 years and older that are not on insulin and who do not have problematic hypoglycemia. Users can wear each sensor up to 15 days before replacing with a new sensor. The device presents blood glucose measurements and trends every 15 minutes in the accompanying app. Users should not make medical decisions based on the device’s output without talking to their healthcare provider.
Data from a clinical study provided to the FDA showed that the device performed similarly to other iCGMs. Adverse events reported in the study included local infection, skin irritation and pain or discomfort.
As part of the Center for Devices and Radiological Health’s strategic priority to advance health equity, CDRH will continue to support innovation that addresses health equity by moving care and wellness into the home setting.
ARTICLE SOURCE: https://www.fda.gov/news-events/press-announcements/fda-clears-first-over-counter-continuous-glucose-monitor
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