The effect of a high-fat diet and sucrose drinking option on the development of obesity in spontaneously hypertensive rats.

1. Energy intakes, body-weights, body fat index, total body fat and interscapular brown adipose tissue (IBAT) were examined in adult male, spontaneously hypertensive, stroke-prone (SHR-SP) rats and normotensive Wistar/Kyoto (WKY) controls given one of four diets for 33 d: (a) a starch diet, (b) a starch diet and a sucrose solution drinking option, (c) an 80% energy from fat (F80) diet, (d) the F80 diet and a sucrose drinking option. 2. The SHR-SP rats showed a complete resistance to obesity on all four diets. For the high-fat diet the WKY animals became markedly obese with approximately two-fold increases in body-weight gain and body fat index when compared with the SHR-SP rats. The gain in total body fat was also significantly greater. IBAT as a percentage of total body-weight did not differ between the WKY and SHR-SP groups. 3. Compared with the WKY animals, the SHR-SP rats showed a reduced food intake but had the same potential to gain weight from the high-fat diet. 4. It is concluded that the resistance to obesity by the hypertensive animals is the result of a diminished energy intake.