A new Arizona State University study found that a fiber-rich diet may reduce calorie absorption while supporting gut bacteria that help regulate energy use and metabolic health.
By yourNEWS Media Newsroom
A new study from Arizona State University suggests the number of calories listed on a nutrition label may not fully reflect how much energy the body actually takes in from food, with researchers finding that gut bacteria may play a measurable role in calorie absorption.
The study used a model known as DAMM, which stands for Digestion, Absorption and Microbial Metabolism, to examine how food is broken down, absorbed and processed by microbes in the colon. Researchers said the findings challenge the long-standing “calories in, calories out” approach to weight management, which critics argue oversimplifies the way the human body handles food.
The research was based on a controlled feeding trial comparing two diets: a typical Western diet, high in processed foods and low in fiber, and a microbiome-enhancing diet rich in fiber and resistant starch. Participants eating the higher-fiber diet absorbed fewer calories per day than those eating the Western diet, while not reporting increased hunger.
Researchers estimated that microbial fermentation in the colon contributes about 15% of usable energy from food. Part of that energy comes from short-chain fatty acids, which are produced when gut bacteria break down fiber and resistant starch.
The findings point to a more complex view of metabolism than the calorie system used on food labels. That system dates back to the late 1800s, when American scientist Wilbur Olin Atwater developed a method using a bomb calorimeter to estimate the energy content of food. The approach remains the foundation of modern nutrition labels, but researchers noted that the human body does not process food like a combustion chamber.
Instead, digestion involves enzymes, hormones, organs and microbes that determine how much energy is released, absorbed or passed through the body. Because of those differences, the number of calories printed on a label may not match the amount of usable energy a person receives.
Processed foods may provide more readily available calories than whole foods, according to researchers. Critics of the traditional Atwater system have argued that calorie-reduction policies can push people toward processed foods rather than more nutrient-dense options. The DAMM model was designed to account for digestion, absorption and microbial metabolism, especially the activity that occurs in the colon.
In the feeding study, the microbiome-enhancing diet produced a different metabolic result than the Western diet. The higher-fiber group absorbed fewer calories overall, while bacterial fermentation generated short-chain fatty acids that may affect appetite and metabolic health.
Research on fermentation in the large intestine has shown that short-chain fatty acids are produced when microbes break down fiber and starch. Those compounds contribute to energy availability while also playing roles in gut and metabolic function.
The study authors said the results “highlight the role of the gut microbiome in modulating energy harvest from the diet.”
The findings suggest that two meals with similar calorie counts may not have the same effect inside the body. The difference may depend on food composition, fiber content and how a person’s microbiome processes the meal.
The ASU research team said dietary guidance should account for the gut microbiome rather than focusing only on calorie totals. No additional independent experts were cited in the report, but the findings align with broader criticism of a calorie-centered approach to nutrition.
Previous research has found that dietary fiber can reduce the absorption of sugars and fats while helping people feel full. One nutrition expert wrote that “fiber in food is perhaps the most important nutrient for health because it singlehandedly protects the liver and feeds the gut.”
The ASU study adds a measurable energy-absorption component to that understanding, showing that diet composition may alter how many calories the body receives from food.
Researchers said the findings support eating more fiber-rich whole foods, including beans, lentils, vegetables and whole grains, while limiting processed foods common in Western diets. Those processed foods may lead to greater calorie absorption because they contain less fiber and require less microbial fermentation.
Dietary fiber has been associated with lower risks of chronic diseases, including heart disease, diabetes and cancer. High-fiber diets have also been linked to greater success with weight loss.
The average American consumes about 16 grams of fiber per day, roughly half the recommended amount, according to recent reports. Researchers said the new findings suggest increasing fiber intake may support metabolic health in ways that go beyond reducing calorie totals.
The study adds to evidence that the quality and source of calories may matter as much as the quantity. A diet built around whole, fiber-rich foods may change digestion, feed beneficial gut bacteria and reduce the amount of energy absorbed from food without increasing hunger.
Researchers said more work is needed to refine the DAMM model and determine how individual microbiome differences may affect personalized nutrition strategies. For now, they said adding more whole, fiber-rich foods to daily meals remains a practical step for supporting gut health, energy balance and overall well-being.
Source: Natural News
Original article
Comments