Exercise does not improve weight loss...

[Roadstr]

Contestants on "The Bigest Loser" will be glad to hear about this!

From Dr. Mikes blog Grist for your insula's mill;

"You say, Mr. Harper, that “people who are exercising - which everyone who wants to lose weight has to do…” Can you show me the data that proves that exercise improves weight loss? I’ll grant you that it sounds reasonable, but can you muster the data that proves it? I can tell you that you can’t because there is no such data. Diet brings about weight loss; exercise doesn’t."

[micki]

Calories in being equal, it only makes sense that increasing calories out via exercise should produce a weight loss effect. You can only lower your intake so far below your metabolic baseline before you get into famine mode and start conservation metabolism; with exercise your output is limited only by your available time and level of interest, ergo is a much larger ocean of calorie differential to dip into.

Also, there are numerous studies which show that exercise, while increasing physcial efficiency, paradoxically creates a "bump" in resting metabolism for up to 36 hours. Stands to reason that bump, if prolonged by ongoing exercise, would result in enhanced weight loss.

Anecdotal evidence: if I have the time and inclination to exercise vigorously 1-3 hours per day vs the 30-45 minutes I am currently able to manage, weight "falls" off me while eating much larger protions and more calories. With my current exercise regimen, weight loss is agonizingly slow, even at 20-30 grams of carbs per day. Yeah, I'm going to quit my job and exercise more. NOT! Exercise may work well for me, but it doesn't pay the bills. SIGH.

[laughingW]

Originally Posted by micki

with exercise your output is limited only by your available time and level of interest

Or limited by excess cortisol resulting from the exercise. Or limited by vigorous exercise increasing the creation of reverse T3. Or limited by overuse injury. Those are just a few examples of realities that prevent the burning of stored fat from exercise - which is what we want.

You might want to read a more nuanced explanation of fuel calories and how they are partitioned. The "a priori" explanation of more calories exercised must mean more fat loss is not a given.

http://www.johnberardi.com/articles/...n/new_view.htm

there are numerous studies which show that exercise, while increasing physcial efficiency, paradoxically creates a "bump" in resting metabolism for up to 36 hours.

There are also studies don't show that. It might depend on the intensity of the exercise.

A new study from scientists at the University of Colorado School of Medicine in Denver offers some reasons why. For the study, the researchers recruited several groups of people. Some were lean endurance athletes; some sedentary and lean; some sedentary and obese. Each of the subjects agreed to spend, over the course of the experiment, several 24-hour periods in a special laboratory room (a walk-in calorimeter) that measures the number of calories a person burns. Using various calculations, the researchers could also tell whether the calories expended were in the form of fat or carbohydrates, the body’s two main fuel sources. Burning more fat than carbohydrates is obviously desirable for weight loss, since the fat being burned comes primarily from body fat stores, and we all, even the leanest among us, have plenty of those.

The Denver researchers were especially interested in how the athletes’ bodies would apportion and use calories. It has been well documented that regular endurance training increases the ability of the body to use fat as a fuel during exercise. They wondered, though, if the athletes — or any of the other subjects — would burn extra fat calories after exercising, a phenomenon that some exercisers (and even more diet and fitness books) call “afterburn.”

“Many people believe that you rev up” your metabolism after an exercise session “so that you burn additional body fat throughout the day,” said Edward Melanson, Ph.D., an associate professor in the division of endocrinology at the School of Medicine and the lead author of the study. If afterburn were found to exist, it would suggest that even if you replaced the calories you used during an exercise session, you should lose weight, without gaining weight — the proverbial free lunch.

Each of Melanson’s subjects spent 24 quiet hours in the calorimeter, followed later by another 24 hours that included an hourlong bout of stationary bicycling. The cycling was deliberately performed at a relatively easy intensity (about 55 percent of each person’s predetermined aerobic capacity). It is well known physiologically that, while high-intensity exercise demands mostly carbohydrate calories (since carbohydrates can quickly reach the bloodstream and, from there, laboring muscles), low-intensity exercise prompts the body to burn at least some stored fat. All of the subjects ate three meals a day.

To their surprise, the researchers found that none of the groups, including the athletes, experienced “afterburn.”

[bpm]

To their surprise, the researchers found that none of the groups, including the athletes, experienced “afterburn.”

It is my understanding that the afterburn is only experienced after short, intense exercise during which only carbs are used. The fat burn occurs after.

Monty