When it comes to diet, the questions that concern scientists are no longer simply “What should we eat?” and “How much should we eat?” Now, it is when we should eat and whether we should eat at all — at least for certain periods of time. The relationship between health and longevity, and fasting (i.e., not eating), was as recently as 20 years ago, seen as the scientific backwater. But this is changing. Longevity research has entered the mainstream, and with it a wide body of research that significant calorie reduction over specific periods of time may actually improve long-term health.
In lab studies, three types of calorie restriction — time-restricted feeding, calorie restriction and periodic fasting diets — have demonstrated benefits to healthspan (the healthy, functional years of one’s life), reducing the risk of age-related diseases. Mice, for instance, have shown protection from obesity (and the associated chronic diseases), improved fitness, and lower risk of metabolic diseases. Now, recent studies are confirming that at least some of these benefits translate to humans. More conclusive studies are in the works that will shed vital light on fasting and long-term health.
We spoke with three leading scientists pursuing research on this topic: Dr. Satchidananda Panda, an expert in circadian rhythms and time-restricted feeding; Dr. Michelle Harvie, a research dietitian and specialist in calorie restriction (often called intermittent fasting); and Dr. Valter Longo, a fasting and longevity specialist, who focuses on cellular health and periodic fasting.