Low-carbohydrate, high-protein diets, known as carbohydrate-restricted diets, are in contrast to the carbohydrate-centric meals typical of the Japanese diet. Carbohydrate-restricted diets were reported to reduce visceral fat, owing to which they have attracted attention and been widely implemented. If, as proposed, carbohydrate-restricted diets are effective in delaying senescence, then Japanese diets have a hidden potential to evolve further. However, long-term carbohydrate restriction in mice was reported to have a negative effect on the cardiovascular system, with shortening of lifespan due to activation of mechanistic target of rapamycin (mTOR). As a result, the safety of long-term adherence to carbohydrate-restricted diets remains doubtful. Recently, we conducted a study using senescence-accelerated mouse-prone 8 (SAMP8) mice to examine the effects of a carbohydrate-restricted diet on aging and skin senescence, and to determine the effect of long-term carbohydrate restriction on the aging process in mice. Here, we discuss the safety of long-term carbohydrate restriction based on the findings obtained from animal studies.