Increased Variation in Body Weight and Food Intake Is Related to Increased Dietary Fat but Not Increased Carbohydrate or Protein in Mice.

Yingga Wu,Chaoqun Niu,Xueying Zhang,Min Li,Sumei Hu,Jianbo Li,Lu Wang,John R Speakman,Dengbao Yang,Guanlin Wang,Li Li,Yanchao Xu,Baoguo Li

doi:10.3389/fnut.2022.835536

Abstract

A variety of inbred mouse strains have been used for research in metabolic disorders. Despite being inbred, they display large inter-individual variability for many traits like food intake and body weight. However, the relationship between dietary macronutrients and inter-individual variation in body weight and food intake of different mouse strains is still unclear. We investigated the association between macronutrient content of the diet and variations in food intake, body composition, and glucose tolerance by exposing five different mouse strains (C57BL/6, BALB/c, C3H, DBA/2, and FVB) to 24 different diets with variable protein, fat, and carbohydrate contents. We found only increasing dietary fat, but not protein or carbohydrate had a significant association (positive) with variation in both food intake and body weight. The highest variation in both body weight and food intake occurred with 50% dietary fat. However, there were no significant relationships between the variation in fat and lean mass with dietary protein, fat, or carbohydrate levels. In addition, none of the dietary macronutrients had significant impacts on the variation in glucose tolerance ability in C57BL/6 mice. In conclusion, the variations in food intake and body weight changes increased with the elevation of dietary fat levels.

Highlights

There is a continuous debate on how food macronutrient composition relates to body weight control [2, 3]. It is still uncertain whether high-fat, high-glycemic-index carbohydrates, including sugar, low protein, or all the three macronutrients, are the cause of the elevated energy intake and obesity in humans [4–6]
We found the coefficient of variation (CV) of body weight and food intake were both significantly related to dietary fat levels (p = 0.036, R2 = 0.07, R2 = 0.07, β = 0.251) and (p = 0.024, R2 = 0.08, R2 = 0.038, β = 0.415, respectively) (Figures 1B,E), whereas there were no significant relationships between CV of body weight or food intake and dietary protein or carbohydrate content (p > 0.05) (Figures 1A,C,D,F)
We found that CV of body weight and food intake was significantly affected by the dietary fat content (p = 0.008 and 0.019, respectively) but not the protein or carbohydrate content (p > 0.05)

Summary

Introduction

Obesity is a major worldwide health issue. Obesity increases the risk of many chronic diseases, including type 2 diabetes, cardiovascular diseases, hypertension, and cancer [1]. There is a continuous debate on how food macronutrient composition relates to body weight control [2, 3] It is still uncertain whether high-fat, high-glycemic-index carbohydrates, including sugar, low protein, or all the three macronutrients, are the cause of the elevated energy intake and obesity in humans [4–6]. The C57BL/6 mouse strain has been suggested to be the best strain for studying metabolic diseases, such as obesity and type 2 diabetes [16, 17] It is consistently described as “obesity prone”; it can be defined as either “diabetic prone” or “diabetic resistant” depending on which sub-strain was used [18]. This strain shows a considerable non-genetic-related variation in body weight gain when fed with a high-fat diet [19, 20]. These non-genetic variations in later-life responses to a high-fat diet seem to stem from the early-life environment of the individual mice, in particular the litter size they were raised in and their early-life nutritional status [15, 24]

Methods

Results

Conclusion