Effects of Cocaine and Fasting on the Intake of Individual Macronutrients in Rats.

Nia Mitchell,Aaron G Roseberry

doi:10.3389/fnins.2019.00805

Abstract

Obesity is a significant problem, and increased food intake is thought to underlie much of the increase in obesity levels. Recently, there has been much discussion and debate about the role of the individual macronutrients, carbohydrates, fat, and protein, in the rise in obesity levels and its associated comorbidities, but overall there has been little study of how different treatments and stimuli that affect feeding impact the intake of individual macronutrients. In these studies, we tested whether two treatments leading to altered feeding, acute cocaine injection and an acute fast, differentially affect the intake of individual macronutrients using a three diet choice paradigm. Cocaine strongly inhibited the intake of each individual test diet (carbohydrate, fat, and protein), but there were no differences between its effects on the intakes of each individual diet. In contrast, an acute fast had little effect on the intake of any of the diets and did not differentially affect the intake of the three test diets. Thus, these studies demonstrate that cocaine can effectively inhibit the intake of feeding independent of its macronutrient content, and significantly advance our understanding of the neural regulation of individual macronutrient intake.

Highlights

Obesity has become a significant problem in the United States and is growing worldwide
Post hoc tests demonstrated that cocaine significantly inhibited the intake of all diets at 1 h and inhibited the cumulative intake of fat and protein at 2 h and carbohydrate at 4 h (Figures 1A–C)
We tested whether acute fasting or cocaine injection differentially alters the intake of individual macronutrients using a three diet choice paradigm

Summary

Introduction

Obesity has become a significant problem in the United States and is growing worldwide. Changes in activity likely have contributed to the increases in obesity levels, this rise is thought to be due primarily to increases in food intake. Foods that are high in fat and/or sugar are highly appetizing and palatable, which increases the rewarding qualities of these high fat/high sugar foods. There is currently significant debate about the contribution of individual macronutrients (fat vs carbohydrate vs protein) to the rise and development of obesity and its accompanying complications (e.g., Hall, 2018). There has been increasing attention to the potential role of added sugars in the rise in obesity levels (Wiss et al, 2018), and studies have shown that diets high in sugars can lead to obesity, diabetes, and addictive/compulsive-like feeding

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Conclusion