Different forms of obesity as a function of diet composition

Area of Science:

• Metabolic research
• Nutritional science
• Obesity research

Background:

• Obesity is a complex metabolic disorder influenced by diet.
• Understanding diet-specific obesity phenotypes is crucial for targeted interventions.

Purpose of the Study:

• To characterize and compare the metabolic phenotype of obesity induced by high-carbohydrate diet (HCD) versus high-fat diet (HFD) or moderate-fat diet (MFD).

Main Methods:

• Adult Sprague-Dawley rats were fed HFD, MFD, or HCD.
• Animals were subgrouped into lean and obese based on body fat content.
• Phenotypic characterization included metabolic markers, gene expression, and enzyme activity measurements.

Main Results:

• Obesity on HFD/MFD was associated with hyperphagia, elevated triglycerides, nonesterified fatty acids, glucose, and increased muscle beta-hydroxyacyl-CoA dehydrogenase (HADH) activity.
• Obesity on HCD showed normal caloric intake and lipid levels, with reduced HADH and increased phosphofructokinase activity, indicating a shift towards carbohydrate metabolism.
• Hypothalamic galanin (GAL) expression correlated with lipid metabolism in HFD/MFD-induced obesity but not in HCD-induced obesity.

Conclusions:

• Obesity phenotypes are diet-dependent, with distinct metabolic profiles.
• HFD/MFD-induced obesity involves hyperphagia, lipid dysregulation, and enhanced fat metabolism.
• HCD-induced obesity presents a different metabolic pattern favoring carbohydrate utilization in muscle.
• These findings suggest multiple, diet-driven mechanisms underlying obesity.