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
Today marks one full year on carnivore. It has been quite the journey and more amazingly beneficial than anything I could have ever imagined.
I started off with carnivore as being just a weight loss hack. I had no idea there would be benefits other than those associated with weight loss. I didn't bother with any of the research on carnivore, the best ways to go about things, I just plunged right in headfirst. It didn't take too long to start learning and figuring things out. (some even the hard way)
I am extremely happy with the measurables. I started at 306lbs with my pant size 44-46. This morning, I weighed 213lbs, losing 93lbs in 12 months and a pant size of 38. If I hadn't started eating for grams of protein per pound the loss would have been well under 100 but I'm good with where and how I landed at 12 months. I have never had blood pressure or glucose issues and the only movement there is my blood sugar is now in the 80's most everyday whereas it was in the 90's before carnivore. My blood pressure has been a consistent 110/60. My cholesterol has improved some as my HDL is staying sort of constant, but my LDL dropped by 35 points on my last visit.
The biggest benefit is that I have NMO/SD, an autoimmune disease that had me on pain and inflammation medicine for just over six years. The prednisone and Neurontin sort of got me thru some rough times when the pain/inflammation was slowing me down. After 4-6 weeks on a strict carnivore diet I found I didn't need the medicine anymore. By the end of that sixth week, I had stopped taking the pain and inflammation medicine altogether. Being pain free is an incredible thing to experience and to get there without a daily medication is really hard to describe. I could not have been any more surprised and could not have been any more pleased with the first six weeks of carnivore.
I'm in the gym three to four times per week and the lifting is starting to grow both in weight and volume. It feels like I am performing better at 55 than 25.
A big thanks to the members of the board and sharing their experiences and thoughts. I'm a bigger fan of hearing someone's personal experiences over a medical study where I have to wonder if the backer had a monetary interest in the outcome of the research or whether the control subjects were really controlled subjects. I can relate to another person's story more than that of a bunch of doctors and control subjects. I really appreciate the exchange of information as it has helped me get over some obstacles here and there.
I'm still learning. After 12 months I think I am easing into carnivore becoming a life style vs. being a weight loss hack. Still, there is work to be done.
Scott