Prof. J. Holloszy studied 18 member of the Caloric restriction society who practised low-caloric diet (1100–1950 calories a day) during six years. 18 members of the control group consumed 1975–3550 calories a day that is more typical for Americans. The aim of the research was to determine how caloric restriction affected health and aging processes in the human organism. It was found that blood pressure and cholesterol level in the middle-aged Americans who were on a low-caloric diet corresponded with those typical for far younger people. The level of C-reactive protein (a marker of inflammation) was 12,5 times lower in the subjects of the experiment than in middle-aged persons. Moreover, J. Holloszy’s group studied long-term effects of caloric or protein restriction on IGF-1 and IGFBP-3 concentration in the blood serum in human. Experiments showed that, in contrast to rats, long-term serious caloric restriction did not lower neither IGF-1 concentration in the blood serum, nor IGF-1: IGFBP-3 ratio in human. It was also found out that consumption of proteins was the key factor determining IGF-1 regulation in human. The investigations showed that caloric restriction reduced the risk of atherosclerosis and diabetes, as well as inflammation level. Thus, restriction of protein consumption may become important component of anti-tumor and anti-aging diets.