Intermittent fasting has become the latest diet craze, not only for weight loss, but also for enhancing better health and longer life— but does it work? Is it more effective than other diets? I decided to investigate.

Everyone from well-known celebrities to everyday, average people are trying it and claiming it is successful. Caloric restriction and intermittent fasting has been practiced for decades. It has gained popularity due to a growing body of research. Over the years, this research has shown that intermittent fasting and calorie restriction can enhance weight loss, cognitive function and help prevent heart disease, cancer and diabetes. It can also slow down the aging process and enhance longevity, but most of the research has been done on mice and rhesus monkeys, and not humans.

I was a member of the American Aging Association (AGE) during my 26 years as Head of Product Development at Twin Laboratories (1974-2001)— a leading U.S. supplier of dietary supplements, vitamins, minerals, antioxidants, phytonutrients, nutraceuticals and sports nutrition products. I attended meetings on a regular basis. Most members of AGE were an elite group of gerontologists and longevity scientists dedicated to study the basic mechanisms of aging for the prevention of degenerative diseases and extend life span, including caloric restriction and intermittent fasting. AGE was founded in 1970 by Denham Harman, M.D., Ph.D., who is often known as “the father” of the “free radical theory of aging.”

I had the privilege of getting to know Dr. Harman. He was a great influence on me back then for his free radical theory on aging, and the potential application of antioxidants in the prevention and treatment of degenerative diseases. Also, as a member of AGE I had the privilege to get to know Roy Walford, M.D. Dr. Walford was a leading authority of the biology of aging and caloric restriction to extend life span. Dr. Walford, a gerontologist and pioneer of caloric restriction, published over 337 papers on the biology of aging.

Walford was also the author of the 1983 book Maximum Life Span, which is a caloric-restricted dieting program to improve health and extend life span with a nutrient-rich and caloric-restricted diet without malnutrition. Dr. Walford followed this caloric-restrictive diet for the last 30 years of his life to hope to live to 120. Sadly, he died on April 27, 2004 at the age of 79 from amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. After his passing, his accomplishments continue to live on to combat the effects of aging and disease.

Dr. Walford’s pioneering work on caloric restriction has lead to the popularity of fasting and intermittent fasting for weight loss. There are conflicting studies on intermittent fasting for weight loss. Intermittent fasting has become increasingly popular, but no long-term randomized clinical trials have evaluated its efficacy … until now! Recently, a yearlong study— the longest study to date— was published in prestigious journal JAMA Internal Medicine. Researchers studied 100 people and found that intermittent fasting did not produce greater adherence to weight loss or protection against heart disease than daily caloric restriction. Researchers found that the intermittent fasters had a harder time following the diets and were more likely to drop out than daily calorie restrictors. This is the largest study to date on intermittent fasting and weight loss! The results of this randomized, large clinical trial found that alternate-day fasting did not produce superior weight loss, weight maintenance and indicators of cardiovascular disease risk. Weight loss and weight regain were similar between the diet groups. One of the negative side effects of the intermittent fasting subjects was an increase in LDL (bad) cholesterol!

I have personally tried alternative-day, intermittent fasting for potential health and pro-longevity purposes and its effect on my feeling of well-being, body composition, as well as on my metabolism and hormone levels. Like the JAMA Internal Medicine study, I also experienced a significant increase in LDL (bad) cholesterol while I was fasting. I was shocked because I thought that my blood work and lipid levels would have improved. At that time, I decided that long-term intermittent fasting is not for me since I have a family history of cardiovascular disease. Also, my testosterone and thyroid hormone (T-4/T-3) levels decreased too. I wasn’t surprised because I felt chilly at times, which is an indicator of a decline in thyroid hormone levels. My theory why my LDL cholesterol may have gone up could have been because of a decline of thyroid hormones. Some of the pro-longevity theories and mechanisms of caloric-restriction diets and aging is slowing the body’s metabolism and generating less reactive oxygen species (free radicals). Also, lowering of glucose, insulin, growth hormone, insulin-derived growth factor (IGF-1) and mammalian target of rapamycin (mTOR); mTOR activation is involved in many forms of cancer survival and proliferation. Research has shown that people with lower growth hormone and IGF-1 levels live longer.

After discontinuing my intermittent fasting diet, I went back on my low-carb Mediterranean diet that is a healthier alternative. After six weeks, my LDL cholesterol, thyroid hormone and testosterone levels went back to normal. Research has shown that the Mediterranean low-carb diet is significantly superior to low-fat diets in decreasing fat storage, including visceral (deep abdominal), liver and heart fat. High visceral fat has been shown to increase metabolic syndrome, inflammation, cardiovascular disease and diabetes. Losing deep subcutaneous visceral fat, as well as haptic (liver) fat, was associated with improved insulin sensitivity and improved lipid profile. For more information on the Mediterranean diet, check out my scientifically-based article on why I think it’s the healthiest diet for 2018 for weight loss, fat loss, living longer and optimal health. Despite the hype, intermittent fasting is not a magic weight-loss cure!