Proteomic Differences in the Hypothalamus May Influence Weight Gain in Rats Fed a Cafeteria Diet

Eating behavior requires a balance between metabolic and hedonic components. Anxiety and dietary type may influence the quantity, patterns, and other aspects of food intake. Modern diets, especially in Western societies, often contain high levels of calories from fat and simple sugars (e.g., cafeteria-style diets). This type of diet may promote overweight and/or obesity in some, although many consumers remain at a normal weight. The mechanisms underlying susceptibility or resistance to weight gain remain unclear. Here, Sprague-Dawley male rats were fed a cafeteria diet for 10 weeks and then classified into quartiles based on body mass. We evaluated locomotor activity and anxiety-like behaviors and analyzed hypothalamic proteomics in overweight (Q4) rats compared with underweight (Q1) rats. Our results showed that locomotor activity and anxiety-like behaviors did not differ across quartiles (p > 0.05). Nevertheless, the expression of several hypothalamic proteins differed between Q4 and Q1 rats. Functional enrichment analysis of these differentially expressed proteins (p ≤ 0.05) revealed changes in cytoskeleton dynamics, synaptic communication, energy production and utilization, biosynthesis of cellular components (including nucleotides and carbohydrates), and regulation of metabolism between Q1 and Q4 rats. Neuro-humoral hypothalamic output regulates metabolism and food intake. Therefore, these functional changes in the hypothalamus may be associated with rats’ susceptibility/resistance to weight gain.