Monday, January 21, 2008

A Look into NBC's "The Biggest Loser"

I teach an online fitness class at my college and I get a lot of questions regarding TV weight loss shows. Most of the questions seem to come from perhaps the most popular weight loss show of all, NBC's "The Biggest Loser". The typical question goes something like this "Why do all of the contestants lose so much weight at first, then seem to taper off dramatically in their losses??"

I was reading my Friend Adam Campbell's blog the other day and I thought his post about the show was worthy of another look.....

The Biggest Loser's Weight Loss Secret
I'll try not to make it a habit to talk about NBC's THE BIGGEST LOSER, but since last night's show may have confused people, I thought I'd try to explain.

Here's the background: Contestants on this show are big people, with women weighing between 200 and 300 pounds, and men somewhere between 300 and 400. In fact, the heaviest contestant is a former college football player named TRENT whose starting weight was around 435 pounds.

Now, in the first week, contestants on the show lost a tremendous amount of weight--around 10 to 30 pounds each, depending on their starting weight. In general, the lighter they were, the less total weight they lost, while heavier people dropped more. Trent, for example, lost 29 pounds in the first week.

After watching this, I was pretty convinced they had contestants on low-carb diets because they were obviously experiencing a large amount of water loss. That is, Trent didn't lose 29 pounds of fat. He lost some fat, but he also lost a lot of water. Why? Because when carbohydrates are restricted, your carbohydrate stores--known as glycogen--are reduced. With each gram of glycogen, which is stored in your liver and muscles, you store about 3 to 4 grams of water. The result: As glycogen levels are reduced, so is water weight.

Keep in mind that the more muscle you have, the more glycogen you can store--so a 400-pound former college football player like Trent can store more glycogen than 210-pound woman who's never worked out. Thus, he's likely to lose a greater amount of water.

Also, a higher protein intake also has a bit of a diuretic effect. So that can lead to even greater water loss. What's more, the contestants were exercising vigorously, which also reduces glycogen.

Before I continue, I should point out that the show doesn't reveal what type of diets the contestants are actually eating. However, near the end of the program, they suggested that people eat a low-fat diet to lose weight, and that Subway offers great options for such an approach. This is nice product placement, but I'm not sure it gives us any insight into the diets of the contestants.

Would you get the same effect of stunning initial weight loss from a low-calorie, low-fat, high-carb diet? "Probably not, simply because protein intake would be lower and glycogen wouldn't be as depleted," says my TNT DIET coauthor, Jeff Volek, Ph.D., R.D. I wouldn't be suprised if they had the people on a low-carb, low-fat, high-protein diet which, in my opinion, is a pretty miserable way to eat, and not particularly healthy. (A low-carb diet, ideally, will be high in fat.) Remember, the producers of the show want amazing results, so I think we can pretty much assume they'll use dietary strategies to ensure this happens.

Still with me? Fast forward to Week 2, the episode that aired last night. This time, the weight loss of the contestants was much less astounding. It seemed to be an average of about 3 pounds, although one woman gained a pound,and another didn't lose any weight. When the contestants saw the results, they were shocked and disappointed. They all expected double-digit weight loss again. And even their trainers seemed dumbfounded, which is just odd. After all, the contestants certainly didn't lose 20 pounds of pure FAT in the first week. Nor did they simply stop losing fat the second week.

So why such a dramatic difference in results from Week 1 to Week 2. I'll let Jeff Volek explain, since he can do so far more eloquently than me:
Body weight on a daily basis can fluctuate plus or minus 3 to 4% on average. So if you take a 400-pound person, the difference between the low and high end (388 and 412 pounds) is 24 pounds.

So there's your 10 to 20 pound weight loss and, combined with the water loss, it's not inconceivable that this is happening.

It's likely that at the second weigh-in they aren't bloated, so they're at the bottom end of the 3 to 4% weight fluctuation, which makes it harder to see the big weight loss numbers.

If you watch the show, you should see much more realistic weight loss numbers from here on out. (Although they may be greater than the average person's since, right now, their only job is to lose weight, and they also may have more to lose than most.)

The lesson: Weight loss can fluctuate dramatically. However, fat loss tends to be linear. In other words, if you're sticking to a solid diet plan, the fat will be coming off at a steady rate of, say, 2 pounds a week, even if your scale shows you losing lots one week and nothing the next.
For example, if you start the
TNT DIET and lose 10 or 12 pounds the first couple of weeks due to an initial reduction in glycogen, you may seem to stall on weeks 3 and 4. Don't be fooled: You probably didn't lose 12 pounds of fat the first two weeks, but you also didn't stop losing fat in weeks 3 and 4. It's just that the scale isn't necessarily providing an accurate gauge of your fat loss from week to week.

This happens all the time, and I refer to it as your "fat loss catching up to your initial weight loss." Case in point: In Jeff's studies at UConn, they may see an impressive weight loss at first, then it slows (even "stops") for a couple of weeks, and then it settles in at a couple of pounds a week. At the end of the 12-week study, when they measure study participants with DEXA--the most sophisticated body fat measurement instrument--they find that the weight loss is typically all fat. And in cases when study participants are lifting weights, fat loss is often GREATER than the weight loss because they're also building muscle. (Click HERE for an example.)
This stuff isn't magic. If your clothes are fitting better, you're losing fat--even if your scale isn't moving.