Effect of Short Term Energy and Protein Restriction on Tissue and Body

The effect of 50 per cent restriction in energy and protein intake in young adult rats has been studied. Two groups of rats were fed for 10 days (Stabilisation, Phase I) an isocaloric diet with two levels of protein: 20 per cent (20 P) or 10 per cent (10 P). At the end of Phase I, each protein group was sub-divided into two groups-a control group and an experimental (Restricted) group -and fed ad libitum or at 50 per cent level of the respective diet for a further period of 10 days (Phase II). The animals were then sacrificed and organs and carcasses preserved for analysis. The results showed highter food consumption and lower weight gain in the ad libitum fed 10 P group compared to 20 P group during Phase II. Fifty per cent diet restriction resulted in nearly identical reduction in weight gain in both the groups. Though nitrogen (N) balance was reduced drastically during diet restriction, it remained clearly positive in the 20 P restricted group, while it was just maintained in the 10 P restricted group. The carcass and tissue composition data showed that the loss in weight was due to extensive depletion of lipids in both the food restricted groups without degradation of the protein component. The study thus demonstrates that short- term 50 per cent diet restriction did not result in protein degradation when maintenance need of protein is met.