Let me throw a few numbers at you. Since 1990, the number of overweight children and adolescents has tripled. And, among all Americans, currently two thirds, or nearly 70% are considered overweight or obese.
The reasons given for this epidemic seem to mostly deal with our sedentary lifestyles: children are not getting enough activity at school, we’re exercising less, our ancestors did much more manual labor than we did, etc. Of course, most of us could be more active. Exercise is good for you on a number of different levels; however, studies have shown that exercise is actually rather ineffective as a weight loss strategy. In fact, what we eat is far more important to losing weight than any other factor.
First of all, studies have shown that physical activity has NOT declined significantly in the last thirty years. We may sit in front of the computer more today, but before that it was the television. And the numbers of people who have gym memberships and participate in workout programs are near all-time highs.
Beyond that, the effect of exercise on weight loss is generally overstated. In fact, if you exercise the way most weight loss specialists, government agencies and medical organizations tell you to, you might even GAIN weight! In 2007, the American College of Sports Medicine and the American Heart Association issued a joint statement in which they recommended 60 to 90 minutes of cardio activity every day. Besides being unrealistic for most of our busy lives, engaging in this “chronic cardio” has the rather unwanted effect of making you incredibly hungry. And as we all know, the hungrier you are, the harder it is to make good choices regarding food. Not only that; working out more often can actually encourage a person to eat something they normally wouldn’t as a “reward”.
Studies bear this out; people who exercise eat more. In a study performed at LSU and published by the Public Library of Science, researchers randomly assigned 464 overweight, non-exercising women to four different groups. Women in three of those groups worked out with a personal trainer for 72 minutes, 136 minutes and 194 minutes per week for six months. The fourth, control group maintained their usual level of physical activity. All of the women were asked to record what they ate, but not to change their dietary habits.
The study showed that women in all of the groups lost weight. But the women who worked out with a trainer several days a week for six months lost only slightly more than the women in the control group. And many of the women in the exercise groups actually gained weight.
Don’t get me wrong…exercise is a must. Regular, even low-level, exercise can reduce your risk for cancer, heart disease, and diabetes. It can also help to alleviate chronic pain while improving energy and stamina. Plus, it can decrease depression while improving overall mental health and cognitive ability. So, you SHOULD exercise. Just don’t expect it to be the cure-all for losing weight.
Let’s take a closer look at the diet component of weight loss. Eating two slices of pizza with a tall soda will run you around 1000 calories. On top of that, to lose one pound of fat requires burning 3500 calories before you even take in any calories.
Or look at it this way: Jogging for 20 minutes burns off about 120 calories, about as much as in a chocolate cookie or two.
So let’s do the math. If you ate 2000 calories a day as recommended by the USDA and you also wanted to burn enough calories to lose a half a pound of fat, the average female would have to run almost 8 hours a day and the average male would have to run almost 5.5 hours a day to accomplish this. Realistic? Not by a long shot.
Now consider what you would have to do to burn off the energy consumed in these foods:
As you can see, even the most strenuous activity levels are no match for poor food choices and an overactive appetite.
Researchers at the Cochrane Collaboration performed what is probably the most comprehensive study done to date on the impact of exercise on weight loss. The researchers reviewed 43 other studies, some of which used diet alone, some of which used exercise alone, and some of which used both diet and exercise to achieve weight loss. In studies where exercise was prescribed, the average workout was 45 minutes, three to five days a week over periods lasting between three months and one year.
The studies that used only diet for weight loss found the average weight loss to be between 5 and 37 pounds. The studies that combined diet and exercise found the average weight loss was 8 to 39 pounds. And the average weight loss in studies that used exercise alone? The weight loss average between 1 and 9 pounds! Many other studies with various methodologies suggest the same results: exercise alone is quite ineffective for weight loss. And in many cases, it can actually be counterproductive.
The bottom line is that exercise is only part of the equation when it comes to weight loss. It is what you eat – not how hard you try to work it off – that matters.
So what should you eat? The diet we recommend is one that is rich in protein and healthy fats. These foods keep you full and satisfied for longer, they stimulate muscle growth, and they do very little to boost blood sugar and insulin (the fat storage hormone). Your carbs should come from low-glycemic sources like whole fruits and vegetables, with the ratio being twice as many vegetables as fruit.
So the next time you think you need to run a marathon for more effective weight loss, just remember that eating smarter wins more than half the battle.