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
TRUTH
Do you shy away from telling people, especially your doctor that you are carnivore?
Do you instead just say things like I’m low carb or I just don’t eat sugar and highly processed foods?
I know I have. And I know why I did it and that was because of fear. Fear of ridicule. Fear of being berated. Fear of not being able to defend my position.
But I’ve come to the realization that as long as we stay in the shadows we can never be accepted.
More and more studies and doctors are coming around to the truth that is carnivore and keto. The truth that mainstream medicine has been wrong all of these years. Unfortunately thought it is still a small niche.
It is said that there have been no long term studies on the effects of a ketogenic diet on the human physiology and that may be true but this is where my realization comes in…we are that long term study, but no one will know about it or be able to document it if we aren’t honest with our doctors and those we encounter.
Our doctors document every visit and every test we take and if we have the courage to be honest with them, no matter what, they will be documenting what we are doing and if we all do this then the medical community will be forced to see the truth in us and eventually all of this data may be compiled to show the world the truth that is carnivore and keto.
At my last doctors visit six months ago I failed to tell my doctor the truth about my new way of eating. I just said very low carb and no sugar or processed foods. No, I wasn’t lying but I wasn’t telling the whole truth and I was doing a disservice to our lifestyle. He thinks I’m just doing a restrictive SAD. That was because I didn’t have the courage to stand up for my convictions and I believe that was due to not being knowledgeable enough or prepared enough to defend my beliefs. That will not happen again.
I have my regular six month checkup next week and the truth will come out. I’m ready to defend my position and show him that I am the proof that carnivore is the proper human diet. So stand strong in your convictions. Educate yourself so that you have the ammunition and courage to defend your position.
Be a part of the study that shows the world that carnivore is the truth.
Be a Positive Deviant
Sent from my iPhone using Tapatalk