Is Fasting A Valuable Weight-Loss Tool?
Fasting has been a part of religious practices for centuries, but it became a mainstream weight loss approach in 2012. After a few recent discussions on the different approaches and potential benefits of fasting, I decided it was time to brush up on the research.
Despite my vested interest, even my eyelids got a little heavy reading through research with sentences like:
“the mechanisms of food deprivation-dependent lifespan extension involve the down-regulation of the amino acid response Tor-S6K pathway as well as of the glucose responsive Ras-adenylate cyclase-PKA pathway resulting in the activation of the serine/threonine kinase Rim 15, a key enzyme coordinating the protective responses.”
Whew – hope you’re still awake! I am a little disappointed to report, however, that despite reading all those “interesting” articles, I still do not have a clear answer on fasting and its value for losing weight.
Mixed Information - But Some Insight
What I did learn is that fasting can be defined many ways, but in general, it’s the abstinence from some or all food or drink, or both, for a specified period of time. The research that demonstrates the potential health benefits of fasting mentions increased lifespan, as well as a reduction in risk for diabetes, heart disease and cancer. But most of this research was done with animal studies. There’s no guarantee that results seen in mice will translate directly to humans.
The human studies that demonstrate fasting as effective for losing weight have had small numbers of participants. In most cases, the diet changes were not followed long-term, and really only pinpoint the overall reduction in calories consumed.
My recommendation on fasting is pretty straightforward: There’s no “one size fits all” approach to weight loss, so fasting might be a fit for some people. If you plan to attempt a fast to lose weight, make sure you speak with your primary health care provider or dietitian prior to starting.
Two Main Ways to Try It
Less-extreme approaches to fasting that allow for some calorie consumption and plenty of water are more likely to be safe for healthy adults. The principal investigator at the Laboratory of Neurosciences at the National Institute on Aging recommends following one of two approaches to fasting:
- Fast two non-consecutive days each week, and when you do, eat only one meal (about 500 calories for women or 600 for men.) The other five days eat normally.
- Fast by not eating between 6 p.m. and 10 a.m. for five days each week.
The key to any fasting-based weight-loss approach is to not overeat on your “normal” days or during non-fasting hours. Make sure to include healthy essentials like lean protein, fruits, vegetables and whole grains, no matter what approach you try with fasting.