HoldsUp

Valter Longo

University of Southern California

Valter Longo is the director of the Longevity Institute at the University of Southern California and the Oncology and Longevity Program at the Institute of Molecular Oncology Foundation in Milan, Italy. His research focuses on the biological mechanisms governing the aging process and the roles of diet, caloric restriction, and fasting in human healthspan. His publications explore the therapeutic and metabolic impacts of fasting-mimicking diets across various conditions, including cancer, type 2 diabetes, and cardiometabolic diseases.

27 claims checked on air: 2 context 1 contradicted 21 supported 3 unverified 1 flagged

What they said on air - context

12 citing their own research

0:39:57needs contextmoderateHow diet and lifestyle regulate longevity with Dr. Valter Lo

Studies on yo-yo dieting and prolonged starvation periods show that they lower metabolic rate, which can lead to subsequent weight gain.

"there's famous papers that have shown what they call the yo-yo diets, right? They have shown that this can actually lower your metabolism if you have this prolonged starvation period. It can lower your metabolism, and then you tend to gain weight." (said at 0:39:57)

Prolonged severe caloric restriction or starvation induces adaptive thermogenesis—an acute reduction in resting energy expenditure beyond what is explained by loss of body mass. However, the speaker's claim that 'yo-yo dieting' (weight cycling) permanently depresses metabolic rate and drives subsequent weight gain is not supported by systematic evidence. Systematic reviews examining weight cycling find that the vast majority of studies show no adverse or permanent reduction in resting metabolic rate from repeated cycles of weight loss and regain. Furthermore, systematic reviews indicate that adaptive thermogenesis tends to attenuate during weight-stable maintenance.

0:43:07needs contextmoderatetheir own paperHow diet and lifestyle regulate longevity with Dr. Valter Lo

The fasting-mimicking diet selectively reduces abdominal fat while sparing subcutaneous fat and preserving or increasing relative lean body mass following refeeding in humans and mice.

"and of course you lose abdominal fat because after a few days this becomes your reservoir. I mean, every—although all the—it doesn't touch subcutaneous fat for some reason, it only goes to the main depot that have this effect. So that's great news, but the muscle is also decreased. But then when you refeed, the muscle is rebuilt... and this, no effect on subcutaneous fat and no or very little effect on even absolute lean body mass. In fact, the relative lean body mass goes up." (said at 0:43:07)

Randomized trial data on periodic cycles of the fasting-mimicking diet (FMD) in humans (such as the 100-subject trial by Wei et al., 2017) show that 3 monthly cycles of FMD reduce trunk and total body fat while largely preserving absolute lean mass and increasing relative lean body mass after normal refeeding. However, stating that FMD has 'no effect on subcutaneous fat' or 'doesn't touch subcutaneous fat' is an exaggeration; while visceral/trunk fat is preferentially mobilized, overall body fat decreases as well.

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