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Dietary self-selection and the Zucker rat
The Journal of Nutrition
|April 1, 1982
Summary
Obese Zucker rats overeat, but do not select diets higher in protein. These findings challenge the idea that impaired protein deposition drives obesity-related overeating in these genetically obese rats.
Area of Science:
- Nutritional Neuroscience
- Animal Models of Obesity
- Dietary Selection Behavior
Background:
- Obesity is often linked to impaired protein deposition.
- Hyperphagia (excessive eating) in obese Zucker rats has been hypothesized to stem from this impairment.
Purpose of the Study:
- To investigate if genetically obese Zucker rats select diets with higher protein content compared to their lean counterparts.
- To test the hypothesis that impaired protein deposition drives hyperphagia in obese rats.
Main Methods:
- Adult male obese (fa/fa) and lean (Fa/-) Zucker rats were given free access to carbohydrate, protein, and fat sources for 9 days.
- Rats self-selected their diets, allowing researchers to analyze macronutrient intake patterns.
Main Results:
- Obese rats consumed 43% more calories than lean rats.
- Obese rats selected a diet comprising 12% protein, 24% carbohydrate, and 64% fat.
- Lean rats selected a diet comprising 33% protein, 37% carbohydrate, and 30% fat.
Conclusions:
- The observed dietary selection patterns in obese Zucker rats do not support the hypothesis that impaired protein deposition is the primary driver of their hyperphagia.
- Dietary protein intake and lean body mass accretion may not be the key factors stimulating overeating in this model of genetic obesity.