Thanks for posting your question.
Restriction of caloric intake (up to a certain point of restriction) has been shown by credible scientific studies to prolong life and reduce disease, IF the person follows an oil-free low-fat plant-based diet of whole unprocessed foods.
Now I will paste from the FB page of Jeff Novick, MS, RD who has generously laid out the URLs for us of these studies:
From Jeff Novick, MS, RD:
Here are the Shintani studies..
Obesity and cardiovascular risk intervention through the ad libitum feeding of traditional Hawaiian diet.
Shintani TT, Hughes CK, Beckham S, O'Connor HK.
Am J Clin Nutr. 1991 Jun;53(6 Suppl):1647S-1651S.
The Hawaii Diet: ad libitum high carbohydrate, low fat multi-cultural diet for the reduction of chronic disease risk factors: obesity, hypertension, hypercholesterolemia, and hyperglycemia.
Shintani TT, Beckham S, Brown AC, O'Connor HK.
Hawaii Med J. 2001 Mar;60(3):69-73.
And here are 2 video's of Dr Shintani discussing his work...
The 7 Step Health Makeover - Terry Shintani, M.D.:
Pathways to Paradise - Dr Terry Shintani - How to Reverse Disease in 10 Days:
And here is the another abstract you might find helpful:
The scientific basis of caloric restriction leading to longer life.
Curr Opin Gastroenterol. 2009 Mar;25(2):144-50.
Purpose of the review: The present review discusses the current state of knowledge regarding the effects of calorie restriction in modulating metabolism and aging.
Recent findings: There are currently no interventions or gene manipulations that can prevent, stop or reverse the aging process. However, there are a number of interventions that can slow down aging and prolong maximal lifespan up to 60% in experimental animals. Long-term calorie restriction without malnutrition and reduced function mutations in the insulin/IGF-1 signaling pathway are the most robust interventions known to increase maximal lifespan and healthspan in rodents. Although it is currently not known if long-term calorie restriction with adequate nutrition extends maximal lifespan in humans, we do know that long-term calorie restriction without malnutrition results in some of the same metabolic and hormonal adaptations related to longevity in calorie restriction rodents. Moreover, calorie restriction with adequate nutrition protects against obesity, type 2 diabetes, hypertension and atherosclerosis, which are leading causes of morbidity, disability and mortality.
Summary: More studies are needed to elucidate the molecular mechanisms underlying the beneficial effects of calorie restriction in humans and to characterize new markers of aging/longevity that can assist clinicians in predicting mortality and morbidity of the general population.