A 2009 study conducted at Southern Connecticut State University
compared the individual and combined effects of interval training and weight
loss on the power-to-weight ratio. They found that training or weight
loss alone each produced the same improvement, about 9%. When both weight
loss and interval training were combined, there was no improvement over the
10-week study period.
The authors of the study speculated that losing weight deprived
the cyclists’ bodies of the ability to benefit from doing high-intensity
intervals. More specifically, inadequate protein intake from dietary
restriction kept their muscles from adapting to the stress imposed by the
sprints. Their conclusion was that weight loss and fitness gains are
incompatible.
Because weight loss, at least up to a point, can improve the
power-to-weight ratio, cyclists often obsess about their weight. Thus it is not
uncommon for cyclists to embark on a crash diet before a major race.
A crash diet seems simple. Just significantly reduce your
daily calories and the weight peels off. However, crash dieting activates
the law of unintended consequences. Here’s why. We know that a pound
contains about 3,500 calories, so if we eat 1,000 fewer calories each day, more
than two pounds will magically disappear each week. And, since we are generally
impatient, we push the daily caloric deficit to help us get to our goal weight
faster. For athletes, however, the consequences of reducing caloric
intake by 750-1,000 calories per day can be significant.
An often-ignored observation was made almost 30 years ago by
researchers at Rockefeller University. They looked at the effect of
calorie deficit on weight loss. As might be expected, the highest caloric
deficit produced the greatest weight loss. What wasn’t expected, however,
was where the weight loss was coming from.
Everyone who goes on a diet is expecting to lose body fat. But
the Rockefeller researchers found that people who practiced moderate caloric
restriction tended to lose the weight as fat. Ninety-one percent of their
weight loss was fat and 9% was lean body mass, or muscle. When the
subjects engaged in a diet involving severe calorie restriction, however, fat
represented 48% of the loss and muscle represented 42%. Expressed another
way, the greater the daily calorie restriction, the greater the loss of muscle
mass.
Ironically, moderate to severe calorie restriction, which
results in loss of lean body mass, is unnecessary. Diets that have
smaller daily caloric deficits (300-500 calories) shed fat while preserving
lean body mass. This was borne out in the Southern Connecticut State University
study described above. The cyclists in the weight-loss group lost about
one pound per week, which translates to a daily caloric deficit of about 500
calories.
The bottom line – Here’s
what we know about weight loss for cyclists:
1. Weight loss can
improve power-to-weight. However:
2. Overt weight loss efforts should be separate from periods of intense
training. And:
3. When weight loss is actively pursued, it should be pursued in moderation to
minimize the loss of muscle mass.
Tagged Products
