New knowledge evaluation helps hedonic overdrive mannequin in high-fat diet-induced mice

Excessive-fat diets trigger weight problems in male mice. The underlying mechanism, nevertheless, stays controversial. After assessing three contrasting concepts, researchers have decided that the hedonic overdrive mannequin gives the very best match, in response to a brand new examine.

The examine, titled “The Hedonic Overdrive Mannequin Greatest Explains Excessive-Fats Weight-reduction plan-Induced Weight problems in C57BL/6 Mice” seems within the journal Weight problems.

“Our work gives some course as to why high-fat/high-carb macronutrient mixtures stimulate overconsumption. The examine is in mice so we have to be cautious about extrapolating to people. Nonetheless, if the impact is repeated in people, avoiding the macronutrient combos that stimulate us to overeat would appear an excellent technique to stop weight problems,” mentioned John R. Speakman, director of the Shenzhen Key Laboratory of Metabolic Well being, Middle for Vitality Metabolism and Copy, Shenzhen Institute of Superior Expertise, Chinese language Academy of Sciences, Shenzhen, China. Speakman is the corresponding creator of the examine.

Consultants clarify that when fed a weight loss program containing greater than 40% fats by energy, the males of many strains of mice deposit massive quantities of physique fats. Nonetheless, the results in females are smaller. The underlying mechanism producing the weight problems impact in males will not be effectively understood as a result of research haven’t carried out measurements steadily sufficient or used a adequate vary of various diets to check amongst various concepts.

Within the present examine, researchers assessed the responses of 240 individually-housed 12-week-old C57BL/6 male mice towards 3 patterns predicted by hedonic overdrive, reverse causality and passive overconsumption fashions. A baseline interval of seven days occurred, feeding all of the mice a typical low-fat weight loss program that contained 10% fats, 20% protein and 70% carbohydrate by vitality. The mice have been then uncovered to 12 completely different diets that diversified of their fats, protein and carbohydrate contents for 30 days. All of the diets analyzed had greater than 40% fats by energy.

Physique weight and meals consumption have been measured day by day over the baseline interval and after switching to the experimental diets for 30 days. Meals consumption was measured from the burden of meals that went lacking from the meals hopper every day. Mice sometimes pulled pellets of meals by means of the hopper bars or floor their meals; subsequently, an intensive search of the cage was made to return any uneaten meals to the hopper earlier than weighing.

Outcomes confirmed that the hedonic overdrive mannequin offered the very best match for the information evaluation. The reverse causality and passive overconsumption fashions weren’t effectively supported. After publicity to the diets, vitality consumption elevated first and physique weight adopted later. Consumption then declined. The height vitality consumption was depending on each dietary protein and carbohydrate, however not the dietary fats and vitality density, whereas the speed of lower in consumption was solely associated to dietary protein.

On the high-fat diets, the burden of meals consumption declined, however regardless of this common discount of 14.4 g in meals consumption, the mice consumed on common 357 kJ extra vitality than at baseline. The truth that they gained weight on this state of affairs is a direct refutation of the mass steadiness mannequin of weight problems.

“Utilizing a number of outlined diets various in macronutrient composition adopted by statistical modeling of meals consumption patterns in male mice over a 30-day interval, this examine reinforces the concept weight loss program palatability, and never vitality content material, drive overconsumption past precise caloric wants. Because the authors acknowledge, the examine additionally reveals that the evaluation of meals consumption patterns requires much more subtle statistical modeling strategies to raised perceive the position of every macronutrient in each the initiation and cessation of consuming,” mentioned Professor Catherine M. Kotz, Ph.D., of the College of Minnesota. Kotz was not related to the analysis.

The examine’s authors famous that it stays a thriller as to why feminine C57BL/6 mice do not need the identical magnitude of response to overconsumption when uncovered to high-fat diets, and added that this might be a worthwhile space for additional analysis.