Actually, the opening post of the thread, while debunking some myths, also embraces some others. For instance, the “muscles burn more than fat” is a deeply entrenched falsehood that I suspect is propagated intentionally by companies that sell exercise equipment/gym memberships. Technically they do, but the difference is trivial as to be irrelevant:
Will More Muscle Rev Up Your Metabolism?
In short, probably not. The average person won’t lose muscle from doing cardio and won’t burn more fat by building more muscle, mostly because one has to eat more than usual (not diet) and lift seriously heavy weights to build more muscle. And even then that person probably won’t build enough muscle to make a difference. Dr. Joseph Donnelly and other leading exercise physiologists conducted a comprehensive review of all the research on exercise and weight loss for the American College of Sports Medicine. While resistance training was recommended for its beneficial role in potentially improving muscle strength and power, the physiologists found no evidence that increasing muscle mass enhanced weight loss, especially when combined with dieting.
Furthermore, there is no evidence that fasting hurts you any more than a regular diet, and in fact can give you the same benefits, and can actually have some additional benefits dieting doesn’t:
WASHINGTON (AP) — Periodic fasting can be just as good for the health as sharply cutting back on calories, even if the fasting doesn’t mean eating less overall, a new study indicates.
Phil Randall isn’t fasting at his home in Kalamazoo, Mich.
By Mark Bialek, AP
Researchers are now planning to see if what works in mice is also good for people.
Several recent studies have reported a variety of benefits from a sharply restricted diet, including longer life span, increased insulin sensitivity and stress resistance.
In the new report, mice that were fed only every other day — but could gorge on the days they did eat — saw similar health benefits to ones that had their diet reduced by 40%, a team of researchers reports in Tuesday’s online edition of Proceedings of the National Academy of Sciences.
The cause of health improvements from cutting back on diet isn’t fully understood, though many researchers had assumed that a long-term reduction in calories was involved.
But the new study by Mark P. Mattson and colleagues at the National Institute on Aging found equal benefits for mice that ate only every other day, but didn’t cut total calories because they ate twice as much on days they weren’t fasting.
Mattson said a study is in the planning stages to compare the health of a group of people fed the normal three meals a day with a similar group, eating the same diet and amount of food, but consuming it within four hours and then fasting for 20 hours before eating again.
“Overeating is a big problem now in this country, it’s particularly troublesome that a lot of children are overweight. It’s still unclear the best way to somehow get people to eat less … One possibility is skipping a meal a day,” Mattson said. “Our study suggests that skipping meals is not bad for you.”
Dr. Carol A. Braunschweig of the University of Illinois at Chicago, who was not part of the study team, said she was intrigued by the suggestion that a drastic change in eating patterns might have benefits.
“With the current epidemic of obesity and physical inactivity facing the U.S. today, identification of a beneficial eating pattern that could address some of the untoward effects of excess weight would be a very significant finding,” she said.
Mattson said an earlier study found that mice that fasted every other day had extended lifespans and the new experiment found the mice also did better in factors involved in diabetes and nerve damage in the brain similar to Alzheimer’s disease.
“We think what happens is going without food imposes a mild stress on cells and cells respond by increasing their ability to cope with more severe stress,” Mattson said. “It’s sort of analogous to physical effects of exercise on muscle cells.”
He said the researchers think this stress occurs throughout the body, and that may be the reason fasting seems to increase lifespan and the animals become more resistant to the diseases of aging.
The dieting mice consumed 40% less food than mice eating normally and lost nearly half their body weight (49 percent) in the experiment, while the fasting mice weighed only a little less than mice eating normally.
In recent years, some nutritionists have recommended eating smaller amounts more often, but this study did not deal with that type of eating pattern.
In the new report, the researchers said both the fasting mice and those on a restricted diet had concentrations of blood sugar and insulin that were significantly lower than mice allowed to eat whenever they wanted. Indeed, insulin levels in the fasting mice were even a bit lower than the dieting ones.
At the end of the experiment all three groups of mice were injected with a toxin that damages cells in the part of the brain called the hippocampus. It’s cell damage there that that is involved in Alzheimer’s in humans.
When the mouse brains were later analyzed the scientists found that the brains of the fasting mice were more resistant to damage by the toxin than the brains of either dieting mice or those eating normally.
As is “starvation mode”
problem with this idea is that, if it were true, no one would die from starvation and obviously people do. Clearly, even if you eat what is obviously too few calories to be healthy, such as an anorexic does, you will continue to lose weight.
So where did this idea – that not eating enough calories makes you not lose weight – come from?
It started with the famous Minnesota starvation study. Some normal-weighted men agreed to live on a compound where their exercise and diet was strictly controlled. For portions of the study, they were on a “starvation diet” which is defined as 50% of the calories your body needs to function.
For me, these days, that’s about 750-850 calories a day. So I was on a starvation diet up for the first four months after my surgery. Yet I lost weight just fine during that period – better than fine, really. Most of the people on The Biggest Loser are also on starvation diets, from what I can tell. They may eat a lot more than I do but they also exercise strenuously 6-8 hours a day. So they are often below 50% of their calorie expenditure for the day. They seem to lose just fine too.
How can this be?!
The answer lies in what actually happened to the Minnesota guys when they were on their starvation diets.
Like most of us on a diet, their metabolisms did slow down. In fact, after they’d been on this diet for a while – we’re talking months, not days here – their body fat percentage got to a point below what is considered minimal to live on (about 5% for a guy, 6% for a gal). At this point, their metabolism had slowed down as much as 40%. But – and this is the important point for those of us on a diet – they continued to lose weight. Even with that big of a slow down in their BMR (Basal Metabolic Rate), they were still operating at a great enough calorie deficit to lose.
If this is true with a 40% slow down, it’s even more true when the slow down is somewhere in the 14 - 22% range, which is more where if falls with normal dieting.
when it comes to fitness, there really is so much bullshit out there that its hard to sort out. Half of it is exercise and nutrition companies propagating it intentionally to convince people the whole thing is more complicated than it really is and thus people need to buy lots of stuff they don’t; the other half is wishful thinking on the part of people who want to think that “eating five to six small meals a day” is a more efficient way to lose weight than not eating or eating less.