1. The effects of isocalorically exchanging dietary starch and sucrose on glucose tolerance, plasma insulin and serum lipids were examined in nine middle-aged subjects. A ‘sucrose’ period in which 70% of dietary carbohydrate was supplied as sucrose was alternated with a ‘sucrose free’ period in which dietary carbohydrate was supplied mainly as starch. Each period lasted 4 weeks; eleven balances were completed.
2. Changes in body weight during the balances were small and statistically insignificant.
3. Fasting blood sugar levels were significantly elevated during the ‘sucrose’ period. During 50 g glucose tolerance tests, blood sugar levels were slightly higher during the ‘sucrose’ period but this difference was not statistically significant.
4. Plasma insulin levels were similar during the dietary periods, both in the fasting state and after 50 g of glucose.
5. Mean levels of serum cholesterol, serum triglyceride and plasma NEFA showed no significant differences between the two dietary periods.
6. It is concluded that glucose tolerance, plasma insulin and serum lipids are not significantly altered by the substitution of sucrose for starch at levels of sucrose intake comparable to those in the Western diet.