For 14 weeks (from the age of 4 weeks until 18 weeks) they fed the male and female mice on one of four diets: (1) a regular (reference) diet; (2) a high fat/low carbohydrate diet (60 per cent fat, 30 per cent protein, 10 per cent carbs, by calorie value); (3) a high protein/low carbohydrate diet (60 per cent protein, 30 per cent fat, 10 per cent carbohydrate by calorie value); or (4) a high carbohydrate/low fat diet (60 per cent carbohydrate, 30 per cent protein, 10 per cent fat, by calorie value)..