Washington DC [US], April 16 (HBTV): Bread and other carbohydrate staples may be doing more than just filling plates—they could be reshaping metabolism, according to a new study. Researchers found that mice strongly preferred carbohydrates such as bread, rice, and wheat, abandoning their regular diet, and gained weight despite not consuming more calories.
Bread has long been a dietary cornerstone, deeply embedded in everyday life across societies. However, with obesity rates continuing to rise, researchers are examining whether heavy reliance on staple carbohydrates remains suitable for modern diets.
Obesity increases the risk of several lifestyle-related diseases, making prevention a major public health priority. Traditionally, research has focused on high-fat consumption as the primary driver of weight gain, which is why many animal studies rely on high-fat diets.
However, carbohydrates such as bread, rice, and noodles are consumed daily worldwide, yet their role in obesity and metabolism has not been studied as extensively. While it is commonly believed that ‘bread leads to weight gain’ or that ‘carbohydrates should be limited,’ it remains unclear whether the issue lies in the foods themselves or in patterns of consumption.
To explore this, a research team led by Professor Shigenobu Matsumura at Osaka Metropolitan University’s Graduate School of Human Life and Ecology studied how carbohydrates influence eating behaviour and metabolism in mice.
The researchers examined whether mice preferred foods such as wheat, bread, and rice over standard chow, and how these choices affected body weight and energy use. The animals were divided into multiple feeding groups, including standard chow, chow with bread, chow with wheat flour, chow with rice flour, high-fat diet with chow, and high-fat diet with wheat flour. Changes in body weight, energy expenditure, blood metabolites, and liver gene expression were tracked.
The findings showed that mice strongly favoured carbohydrate-rich foods and stopped eating their standard chow. Although total calorie intake did not increase significantly, both body weight and fat mass rose. Mice that consumed rice flour gained weight similarly to those that ate wheat flour. In contrast, mice on a high-fat diet combined with wheat flour gained less weight than those on a high-fat diet with chow.
‘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,’ said Professor Matsumura.
Further analysis indicated that weight gain was not driven by overeating, but by reduced energy expenditure. The study also found higher levels of fatty acids in the blood and lower levels of essential amino acids. In the liver, fat accumulation increased, along with the activity of genes linked to fatty acid production and lipid transport.
When wheat flour was removed from the diet, both body weight and metabolic abnormalities improved quickly. This suggests that reducing reliance on wheat-heavy diets and adopting a more balanced nutritional approach may help regulate body weight more effectively.
‘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,’ Matsumura said.
He added, ‘We also intend to investigate how factors such as whole grains, unrefined grains, foods rich in dietary fibre, their combinations with proteins and fats, food processing methods, and timing of consumption affect metabolic responses to carbohydrate intake. We hope this will contribute to achieving a balance between taste and health in nutritional guidance and food development.’
The findings were published in Molecular Nutrition & Food Research.
(ANI)