It’s a question that many nutrition researchers have debated for decades: Which diet is best for weight loss?
Now, researchers at the University of Illinois have made a discovery that they say could help provide the answer.
The scientists found that mouse food consisting of one of two types of protein was associated with less body fat than a standard diet.
They also found that eating a high-protein diet can have a beneficial effect on the trillions of healthy bacteria in the gut, which have been linked to hunger and appetite control.
The study, conducted on mice, aimed to determine how high-protein diets affect the animal’s gut microbiome and body composition, including total weight and fat.
Mice fed a diet consisting largely of different types of proteins weighed less and had lower fat mass. The proteins they consumed can be found in most meat, eggs and various types of fish
Scientists conducted a month-long experiment on 16 mice. For the first two weeks of the experiment, the mice were fed a standard diet of mouse chow that consisted mainly of carbohydrates.
Over the next two weeks, they were divided into four groups and given a new food containing one of two types of protein, both found in meat, poultry and seafood.
Scientists collected daily samples of the mice’s feces to monitor the proportion of healthy gut bacteria, as well as measurements of their body fat.
At the end of the study period, it was revealed that the mice eating the high-protein diets experienced greater loss in both body weight and fat than those on the standard high-carb diets.
One type of protein came out on top as the most impactful branched-chain amino acid given to any of the groups.
Branched chain amino acids are commonly found in chicken, beef and turkey, salmon, tuna, shrimp and milk.
They also found that undigested proteins are fermented in the intestines and produce beneficial byproducts, such as short-chain fatty acids, which help the body regulate appetite and absorb vitamins.
Previous studies have pointed to the positive effects of a protein-rich gut microbiome.
Fermentation of proteins leads to the development of certain beneficial bacterial strains, such as lactobacillus, which can seek out and destroy harmful bacteria.
Samson Adejumo, a biology doctoral candidate at the University of Illinois who led the research, said the findings contribute to a “critical foundation” in our understanding of how proteins influence our gut microbiome and ultimately our health.
Previous studies have shown that an abundant gut microbiome can increase the rate at which calories are burned and regulate the hunger signals sent between the brain and stomach.
It also modulates the movement of bile in the digestive tract, which plays a role in the digestion and absorption of fat.
While the experiment was conducted in mice, other research has concluded that increasing the amount of protein from food in the diet promotes muscle toning, growth and strength.
Protein should make up 10 to 35 percent of daily calories, and athletes should consume one to two grams per kilogram of body weight, the official guideline advises.