Tonawanda News

June 9, 2013

Fit for Life: Don't be like 'Crash Diet Kelly'

The Tonawanda News

Tonawanda News — I’d like to try to explain why crash diets don’t work. So, I’d like you all to meet ‘Crash Diet Kelly.’

Kelly is a “yo-yo” dieter and this is a fairly common trait, especially among women who hope to lose a few pounds before an important event such as a vacation or a wedding. Many of us do the same just after the New Year, when holiday eating and drinking tanks all our efforts to eat healthy.

In attempt to offset months of poor eating, some start off drastically reducing calories and increasing activity level, most likely from a sedentary state.

This will lead to weight loss, however it will be mostly muscle tissue. Maintaining an excessive cardio-exercise regime like running or aerobics, while consuming inadequate calories, can only last for so long.

Once the trainee resumes “normal eating” or a reduction in activity, weight gain and an increase in body fat is inevitable. The unfortunate thing is that this weight gain will be all body fat.

This means you could weigh the same (or slightly more) than when you started your crash diet but have a substantially slower metabolism.

Why is metabolism important? Your metabolism is important because it controls how much (or how little) you can eat to maintain your body weight. Those with a faster metabolism will be able to consume more calories than those who unfortunately have a slower metabolism.

Why is a metabolism slow? There are a variety of reasons. Including these:

• Set point theory — In a nutshell, this theory states that each individual has a weight/bodyfat percentage that it will strive to maintain.

• Loss of muscle/weight gain — As you age (unless you’re proactive with weight training) your body will lose muscle tissue, and muscle tissue is more metabolically active than adipose (bodyfat). Less muscle tissue means a slower metabolism. Your body would then be conditioned to store fat, something we definitely do not want.

Now let’s look at Crash Diet Kelly. Say that she weighs 150 pounds and has 30 percent body fat. Her lean body mass is 105 pounds. This means she has 45 pounds of body fat on her frame.

Assuming she does a few things less than ideal (drastically cuts calories, does tons of cardio and very little to no resistance training) she could lose a decent amount of weight quickly. Lets say she drops 12 pounds.

After her desired event (cruise, wedding, etc.) takes place, she relaxes on her “diet.” Kelly starts doing less cardio, down from six days a week to “only” four and she starts eating another 250 calories per day.

Neither “indiscretion’ would be that bad for an individual with a healthy metabolism. But for someone who crash “dieted” this is a recipe for disaster. As the weight comes back quickly, body fat accumulates and Kelly is back at her pre-diet weight of 150 pounds.

But, her clothes don’t fit like they did before her diet. What happened? Well, Kelly is now 34 percent body fat. Her lean mass is now 99 pounds down from 105. Kelly has 51 pounds of fat versus 45 at the start of her diet.

She has 6 more pounds of fat on her — or 6 less pounds of muscle. On average each pound of muscle will burn 50-75 calories per day. So because of those 6 pounds of muscle Kelly lost … she will burn 300-450 less calories per day. So all the hard work is wasted and she is literally worse than when she started.

In the next article we will discuss on how to improve a slow or damaged metabolism.

Chris Tybor is a personal trainer and owner of Christfit, which has locations in Lewiston and Niagara Falls. For more information visit