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
As previously stated, Carnivore has been an amazing journey thus far, and I feel like there is still a ways to go.
My metabolic numbers are what I consider great. BP is 100 over 65 on the regular. Blood glucose is in the upper 70's to low 80's. Total cholesterol dropped from 221 to 212. My blood showed at some point I may need some iron but for now carnivore will be my supply. My Vitamin D jumped to 55. HDL is at 39 and LDL dropped from 187 to 152 and back to 164 over the last five months. I am sure part of the fluctuation can be from adjusting protein and not hitting my fat content, to seeing that error and maybe overly bumping fat back up. Plus, throw in some regular fasting and I am sure there is some 'extra fat' in my blood. Maybe not the best numbers in the world but moving from well over 300 to 215 in 13 months, I'm more than satisfied and feel like I am in a pretty good place.
Thru the carnivore approach and increasing effort in lifting and working out my total testosterone moved from 381 to 481 from August '24 to May '25. No TRT treatment and no supplementation.
I had a couple of 20-somethings doubt my work out routine a few weeks ago so I invited them to come along. At less than fifty burpees both quit. I'm not sure if I felt good as a 55 year old or felt bad at this 20-something crowd. In my 20's I would have died from heat exhaustion before some old guy outperformed me. Times have changed and sometimes I am just too dumb to quit.
I have been scanning articles and videos for 'elite' type athletes who practice carnivore or even animal based. It is one of my new carnivore interests.
I am debating going to the gym to play full court basketball in the morning with a bunch of 20-year-olds after night shift. I think I have bitten off more than I can chew. If nothing else my body will tell my mind on what is the correct page. LOL
Scott