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
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The carnivore diet is as easy as just eating meat, right? This is basically true. But if you follow some famous carnivore proponents on socail media or YouTube you may get confused. Some carnivores might be seen eating cheese or using heavy cream, and others may be caught using some herbs and spices on their food. I've spotted one drinking a diet soda, and then others boast about eating fruit and honey. So, like, what gives?
What Is the Carnivore Diet?
Different Types of Carnivore Diets
The Lion Diet (Elimination Diet) - This diet consists of unprocessed ruminant flesh, usually beef, but could also include lamb, elk, etc, with salt, and only water. This is usually a zero carb carnivore diet. Many peple eat this way because they get inflammation and other physical symptoms when they eat other food. This is also a perfect way to start an elimination diet, starting with 30-90 days of Lion Diet and then slowly reintroduce foods one at a time to see how you react to them.
The Standard Carnivore Diet - This is the most dogmatic and strict form of the carnivore diet, which involves consuming only water, salt, and meat, whether ruminants, poultry, pork, or seafood, including eggs and fish roe. No dairy, no seasonings, no supplements, and no plant foods are allowed. This diet is based on the premise that humans are designed to eat only animal foods, and that plant foods are harmful or unnecessary for optimal health
The Nose-to-Tail Carnivore Diet - This is a more nutrient-dense version of the carnivore diet which includes any animal flesh, as well as organ meats such as liver, kidney, heart, and brain. Organ meats are rich sources of vitamins, minerals, antioxidants, and co-factors that are essential for various bodily functions and may prevent deficiencies that may arise from eating only muscle meats. This may often mean zero carb depending on the type of seafood and the amount of eggs. This is also sometimes called ancestral carnivore or restrictive Paleo.
Any Animal Products Carnivore Diet - This slightly more flexible version of the carnivore diet includes all animal flesh and any animal byproducts that can be produced by the animal kingdom. This would include dairy products such as milk, yogurt, heavy cream, cheese, butter & ghee, as well as things like bacon, sausage, pork rinds, and deli meat. This is also sometimes called Zero Carb Carnivore by those who still avoid milk sugars and certain seafoods.
Animal-based "Carnivore" Diet - Primarily animal sourced products but also allows participants to partake in some carbs found in nature, including some occasional bee honey and some fruitage that can be eaten based on seasonal availability. It's basically a mix of carnivore and Paleo. Animal-based dieters are still focused on animal consumption and avoiding plants (except their fruitage) and plant toxins with little to no regard for carbohydrate consumption. Dogmatic carnivore purists will argue that this is not "true" carnivore.
Carnivorish/Ketovore Diet - This Meat-based Keto lifestyle still focuses primarily on animal products but does allow for some plant-based oils like coconut oil, olive oil, and avocado oil (the good kinds) along with the inclusion of some low carb vegetables, with the aim of limiting carb consumption to 10g (ketovore) or 20g (keto) per day. This version permits the use of some spices and herbs to enhance the flavor and variety of the meals as well. Dogmatic carnivore zealots will argue that this is not "true" carnivore.
Which Carnivore or "Carnivorish" Diet is Right for Me?
Rather than be dogmatic, all of the above can fall under the umbrella of what Dr. Ken Berry M.D. refers to as "The Proper Human Diet". A proper human diet is one that is all natural, uninflammatory, minimally processed, and low in carbohydrates (meaning about 100g or less per day). The key to optimizing your health is to find out where on the spectrum you fit in the best. For some this may mean being absolutely strict about being a pure carnivore and avoiding plants and fruitage altogether. For others this may mean low carb, non-starchy vegetables that have a minimal impact on insulin and glucose levels are fine. Still others may choose to eat fermented or pickled vegetables and some may enjoy some fruit, but only seasonally or sporadically.
The amount and frequency with which one consumes fruit and vegetables on the carnivore or animal-based diet may vary depending on the individual’s goals, preferences, and tolerance. The key is to listen to your body and adjust accordingly. If you notice any negative effects from eating vegetables, such as bloating, gas, diarrhea, or cravings, you may want to reduce or eliminate them from your diet.
So where on the spectrum are you? What kind of carnivore dieter do you tend to be?
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