Sugar and fat bingeing have notable differences in addictive-like behavior

Abstract

Ingestion of different nutrients, such as fats and sugars, normally produces different effects on physiology, the brain, and behavior. However, they do share certain neural pathways for reinforcement of behavior, including the mesolimbic dopamine (DA) system. When these nutrients are consumed in the form of binges, this can release excessive DA, which causes compensatory changes that are comparable to the effects of drugs of abuse. In this article, we review data obtained with animal models of fat and sugar bingeing. The concept of "food addiction" is described and reviewed from both clinical and laboratory animal perspectives. Behavioral manifestations of addictive-like behavior and concomitant alterations in DA and opioid systems are compared for sugar and fat bingeing. Finally, in relation to eating disorders and obesity, we discuss how fat may be the macronutrient that results in excess body weight, and sweet taste in the absence of fat may be largely responsible for producing addictive-like behaviors that include a withdrawal syndrome.

FIGURE 1

Sugar and nonpurified diet (chow) intake during the 28-d access period in a rat model of sugar bingeing. Rats with intermittent sugar + nonpurified diet escalated their total daily sugar intake over time (A). Rats with intermittent sugar + nonpurified diet ate less nonpurified diet than the intermittent nonpurified diet group and the nonpurified diet ad libitum control group (B); however, the groups did not differ in total daily energy intake (1 kcal = 4.184 kJ) (C). Values are means ± SEM, n = 9–10/group. Reproduced with permission from Avena et al. (23).

FIGURE 2

Energy intake and body weight alterations in a rat model of fat bingeing. Total daily energy intake during wk 3 of access expressed as energy derived from standard nonpurified diet (chow) (white) versus sweet-fat nonpurified diet (black) (A). The 2-h daily sweet-fat group and a group that received 2-h of sweet-fat diet only on Mondays, Wednesdays, and Fridays (2-h MWF Sweet-fat) both consume >50% of their daily energy from sweet-fat diet when it is available. A sawtooth pattern emerges for the 2-h daily sweet-fat group in which they decrease in weight prebinge and increase in weight postbinge each day (B). However, despite this fluctuation in body weight throughout the day, the rats with 2-h daily sweet-fat gained significantly more total body weight than rats fed standard nonpurified diet ad libitum (1 kcal = 4.184 kJ) (C). Values are means ± SEM, n = 10/group. *Different from the standard chow ad libitum group, P < 0.05. Adapted with permission from Berner et al. (22).