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Tuesday, September 7, 2010

Weight-loss Myths, Part 2

Here at Jungle Miami we tell you things that go against what you might call "common knowledge". We tell you to eat carbs and fat, and to throw away those no-carb-high-protein drinks. We tell you that those protein bars are the same as a snickers bar (it's true...compare the ingredient list of a protein bar to a snickers bar...there's only one ingredient that's different...protein powder!).

We do this because, without you knowing it, the media has brainwashed us into believing the world is flat, and that and the sun revolves around the earth, when it comes to exercise, nutrition, and weight-loss. Why do they do this? Well, according to ResearchWikis.com:

"The sports drinks market is approximately US $300 billion in terms of sales worldwide in 2005."

Need I say more?

Just like Galileo was persecuted because he said the earth revolves around the sun, we too get strange looks and sometimes heated tempers when we say things like:

"Drink chocolate milk instead of protein drinks; and eat all the carbs you want, even after 6 o'clock."

So, for the next few days we are going to share some weight-loss myths that the National Academy of Sports Medicine outlines in their "Solutions to Weight Management" course. We tackled out first myth yesterday; the high-carb/low-protein diet.  Let's tackle a couple more today:


Eating at Night Causes Weight Gain

This myth combines both biological and behavior aspects. There is no magic time when the body is better or worse at storing fat. Our bodies function on a continuum and if, over time, an energy surplus prevails, weight gain will occur. However, if the person has not eaten all day long and heads into the evening hours starving, she or he is very likely to consume more than they need. Likewise, if a person is mindlessly snacking all evening, there’s a strong probability that excess calories will be consumed.

Studies show that the most difficult time of day for people to resist overeating is during the evening and nighttime hours (17). Resulting weight gain, however, occurs not because the foods were eaten at night but because of consumption of calories beyond one’s needs.


You Have to Exercise at a Low Intensity or You Won’t Burn Fat

 Despite an enormous amount of research on the topic, some confusion remains over the relationship of cardiorespiratory training intensity to fat expenditure.

This fairly complex physiology has given way to one of the more common weight-loss misconceptions: You have to exercise at a low intensity or you will not burn fat. As with some of the other myths, there’s a distorted grain of truth inside this one as well.

Physiology labs have sophisticated equipment to differentiate the fuels being used during exercise of different intensities. Fat contribution to total energy expenditure is related to intensity; however, it is not that simple. During exercise of low-intensity, there is a higher percent contribution from fat as a fuel source (Table 1). However, this is offset by the higher energy expenditure during high-intensity exercise.  Assigning some values to the concept will make this concept more explicable.


Table 1. Calorie and Fat Expenditure

Type of exercise
Total calories expended* Percent contribution from fat* Total fat expended*

Low-intensity exercise
100 60% 60 fat cal

High-intensity exercise
50040%200 fat cal

* This is a fictional amount used as a demonstration.

While the percent contribution from fat is higher with the low-intensity exercise (60%) than in the high-intensity exercise (40%), the total calorie expenditure (as well as the contribution from fat calories) is greater in high-intensity exercise. Partly to blame is the cardiovascular equipment in fitness facilities that is erroneously labeled “fat-burning zone.”

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