Greater starvation resistance requires physiological changes which are likely to trade-off with other fitness-related traits. By reducing the amount of nutrition in particular protein offered to adult flies increases their starvation resistance, with up to twofold difference between females previously fed ad labium yeast than those given no yeast. Sisodia and Singh also found that south Indian populations of Drosophila ananassae, which feed on carbohydrate rich fruits, have higher starvation resistance than north Indian populations which feed on protein enriched fruits. For starvation there is good evidence that an increase in the lipid content of adults underlies increased resistance to starvation. There are several factors which contribute to starvation resistance although their general importance is uncertain. An increase in body weight has been associated with starvation resistance and body weight may reflect the total reserve of energy storage compounds carried by organisms. However, a reduced rate of respiration could underlie starvation resistance; there was no correlated change in respiration rate in lines selected for female starvation resistance. There is also evidence for an association between starvation resistance and carbohydrate metabolic reserves, particularly as the association between starvation and energy reserves is strongest when both carbohydrate and lipid components of these reserves are considered. Our earlier results suggest that flies from different localities differ in their susceptibility to starvation because of differences in their propensity to store body lipid. A high protein requirement when producing eggs might reflect that synthesis of the egg-yolk protein vitelline in females is dependent on the incorporation of amino acids. The interesting finding of this study is that flies evolving under protein rich condition had reduced egg to adult viability suggest a trade-off between egg to adult survival and egg production. This trade-off could suggest that a limiting shared resource is divided between the two traits. However, the trade-off was found on both diet types. Thus it is more likely that the trade-off is caused by antagonistic pleiotropy. Kristensen et al. found trade-off between egg to adult survival and body mass in protein rich diet in Drosophila melanogaster. They also explained that this event is caused by antagonistic pleiotropy, whereby alleles coding for larger body size which is advantageous under protein-enriched conditions, at the same time have a negative effect on physiological processes that affect survival. This result can be extrapolated to other organisms including humans. It introduces interesting challenges and potentials in relation to breeding strategies and diet recommendation. Furthermore, results from this experiment indicate that trade-off between fitness traits may exist when ABT-263 dietary protein content is varied. This may potentially have consequences for populations that in recent times have changed their diet fundamentally. Our data suggest that such a change may simply provide an immediate challenge to the generations exposed to the change. Evolutionary adaptation to the new diet may potentially produce an additional risk diet through unfavorable trade-offs. We show many surprising differences in stress adaptation, life history traits and reproduction between flies developed on two different nutritional regimes. These data raise issues about the role of diet and specifically the dietary Protein: Carbohydrate ratio in maintaining variation for these traits within and among population.