Racing Weight: Lose Weight or Lose Fat?

Not all weight loss is good weight loss.

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Not all weight loss is good weight loss.

Written by: Matt Fitzgerald

When a person says she wants to lose five or ten pounds, it’s understood that she means five pounds of fat, not five pounds of muscle, bone mass, or body water. But when the typical dieter loses five or ten pounds, barely half of that weight is fat. The other half is, in fact, muscle, bone mass, and body water.

Losing weight is not as good as losing fat. If you lose five or ten pounds of mixed fat mass and lean body mass, your health, appearance, and endurance performance will not improve as much as they will if you lose an equal amount of pure fat.

Here are some tips to ensure that any and all weight you lose in pursuit of your ideal racing weight is body fat.

Track Your Body Composition

Ensuring that fat loss accounts for all of your weight loss begins with consistent monitoring of your weight and body composition. This is easily done with a body fat scale such as a Tanita Ironman. Step on the scale once a week to check your weight and body fat percentage. Multiply your weight by your body fat percentage in decimal form to obtain your body fat mass. If changes in your total body weight equal changes in your body fat mass, then 100 percent of your weight loss is fat loss.

For example, suppose your body weight four weeks ago was 160 lbs, and your body fat percentage was 15. This means your body fat mass was (160 lbs x 0.15 =) 24 lbs. Now suppose your body weight today is 156 lbs and your body fat percentage is 12.9. This means your body fat mass is now (156 x 0.129 =) 20.1 lbs. So your total weight loss is 4 lbs and your body fat mass loss is 3.9 pounds. Congratulations! Almost all of your weight loss has been fat loss.

Cut Calories Moderately

The surest way to lose lean body mass along with fat is to cut your daily calorie intake drastically. In a study performed at Rockefeller University, one group of subjects cut their energy intake by 700 calories a day, while a second group cut their energy intake by 300 calories a day. The first group lost more total weight, but it was only 48 percent fat—the rest was lean body mass. Meanwhile, the weight lost by the second group was 91 percent fat.

When trying to lose excess body fat, limit your daily energy deficit to roughly 300 calories per day. This is especially important during periods of intensive training, when you need plenty of energy to fuel workouts and recovery.

Eat Plenty Of Protein

Anytime you reduce your daily calorie intake to promote fat loss, you should also increase the percentage of your daily calories that come from protein. This measure will help you preserve muscle and lose only fat. Muscles are made of protein, after all.

In a 2010 study conducted at the University of Birmingham, England, two groups of athletes cut calories equally to promote weight loss. But one group got 15 percent of their daily calories from protein (which is about normal) while the other bumped their protein intake up to 35 percent. The 15 percent group lost more total weight, but more than half of that weight was lean body mass. Members of the 35 percent protein group lost just as much fat without losing any muscle.

Now, a 35 percent protein diet is a little much for endurance athletes, who need their carbs to fuel workouts. But as an athlete you can increase protein’s contribution to total calories during weight loss in a way that doesn’t sabotage your training by simply maintaining your current level of protein intake (in terms of grams per day) while cutting fat and carbs from your diet to achieve your desired calorie reduction.

Strength Train

Lifting weights and other forms of strength training will also help you retain muscle during periods of weight loss. Strength training should be a part of your routine at all times, for its injury-prevention and performance-enhancement benefits, but when you’re trying to shed fat, there’s a third reason to do it. A little goes a long way. Just two, 30-minute, full-body strength sessions per week are much better than nothing.


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