Is Intermittent Fasting a Good Way to Lose Weight?
There’s an article online in the Los Angeles Times that explores the pros and cons…for some people, simply not eating 1 – 2 days per week is an easier way to restrict calories and lose weight, than to stick with a conventional diet program. This sort of regime is also favored as a way to achieve the alleged longevity-enhancing benefits of chronic caloric restriction without actually having to restrict calories all the time.
Taking that inclination into account, some people are adopting an unusual solution to overeating. Rather than battling temptation in grocery stores, restaurants and their own kitchens, they simply don’t eat. At least not at certain times of the day or specific days of the week.
Called intermittent fasting, this rather stark approach to weight control appears to be supported by science, not to mention various religious and cultural practices around the globe. The practice is a way to become more circumspect about food, its adherents say. But it also seems to yield the benefits of calorie restriction, which may ultimately reduce the risk of some diseases and even extend life.
…Put simply, intermittent fasting appears to offer the same advantages as long-term calorie restriction — defined as eating at regular times but consuming 25% to 30% fewer calories than what is recommended for that person based on age, size and gender (see accompanying article). People who eat this way tend to do so by filling up on nutrient-dense but low-calorie foods. They get all the protein, fiber, vitamins and minerals the body absolutely needs — and very little else.
Some personal experiences are recounted in an accompanying article.
Personally, I’m somewhat dubious about the concept, both from the science side of things as well as personal. Much of the research on calorie restriction – as the article notes – is based on non-human models. And while there may be health benefits for humans, most of the feedback is from people who have transitioned from overweight and unhealthy, inactive lifestyles to being leaner and fitter. To the extent that this sort of program has helped certain people succeed, I’m all for it…for what it’s worth, there’s zero evidence that it does any harm.
From my point of view, however, there’s really zero evidence (at this point) that it actually extends human lifespan, either…and the most recent animal research just dumped some cold water on the concept.
If you are a mouse on the chubby side, then eating less may help you live longer. For lean mice – and possibly for lean humans, the authors of a new study predict – the anti-aging strategy known as caloric restriction may be a pointless, frustrating and even dangerous exercise.
“Today there are a lot of very healthy people who look like skeletons because they bought into this,” said Raj Sohal, professor at the University of Southern California’s School of Pharmacy.
By measuring the animals’ metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.
“Your energy expenditure and your energy intake should be in balance,” Sohal said. “It’s as simple as that. And how do you know that? By gain or loss of weight.
“The whole thing is very commonsensical.”
For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice – both in DBA and leaner C57 individuals – actually shortened life span.
…”Our study questions the paradigm that caloric restriction is universally beneficial,” Sohal said. “Contrary to what is widely believed, caloric restriction does not extend (the) life span of all strains of mice.”
It’s that comment about “very healthy people who look like skeletons” that resonates with me…it’s no surprise to me that the LA Times article is accompanied by a picture of a man who’s the very picture of “health” – in that haggard, drawn “I run marathons before breakfast” sense. I know people who look like that. And it’s the very antithesis of what my colleagues and I strive for, which is to be lean, physically strong and muscular.
When I tried intermittent fasting, I found that – while it wasn’t physically hard to do – it was mentally draining. I write and do research for a living, and found that fasting made it virtually impossible to concentrate on my work. I was fine as long as I was moderately active: doing chores or taking walks. But I couldn’t cut through the mental fog long enough to be productive – which is ironic in light of caloric restriction’s alleged benefits on cognition and memory. After a couple of weeks, I said “screw this” and went back to eating my normal (healthy) diet. It was a huuuuge relief.
My take on the whole thing is this: if you’re overweight and have certain “warning signs” (i.e., insulin resistance, high cholesterol/triglycerides, high blood pressure, etc.), and have a history of yo-yo dieting, then intermittent fasting could well be a viable, long term strategy for losing excess weight and improving your health status. But it’s certainly not for everyone…especially for those of us interested in increasing lean mass and strength performance.
