A Tenuous "Alli"ance

It appears that GlaxoSmithKline has recieved approval to market Alli overseas to our European cousins.

This means the product will now be proposed for final approval by the European Commission and marketing authorisation could be granted in the coming months. On licence grant, orlistat 60 mg would be the first licensed weight loss aid available without prescription throughout Europe.

You hear that? An FDA-approved weight-loss supplement! It's a miracle!

Alli was actually released to US markets last summer as one of the more unusual Rx-to-OTC product conversions that we've seen recently. Popular once prescription-only Zyrtec I expected, but Alli was really out of left field. I actually meant to blog about Alli when it was released, but somehow it got away from me. Now I can do so to commemorate its release across the pond.

What is Alli? Alli contains the same active ingredient as a prescription drug that was developed by the Swiss company Roche Pharmaceuticals--the generic name for it is orlistat. It is the first over-the-counter drug approved as a weight loss aid by the FDA, mostly because there's good clinical data that it's actually effective when used properly.

OTC "diet pills" generally contain high doses of stimulants/caffeine, claim to suppress appetite, or somehow purport to "melt fat" or "block calories." Some stimulant weight-loss supplements contain as much caffeine per capsule as three cups of coffee and have "serving sizes" of two or three caps at a time! Clever wording is usually employed to conceal the simplistic nature of these products--Zantrex-3 refers to its caffeine content as "a proprietary xanthine-based stimulant." Caffeine is part of a chemical family called methylxanthines. Other times numerous herbal ingredients or Latin names for botanicals obscure the true content of the supplements except to the most attentive consumers.

Alli, true to its claims, is different. How does it work?

First, a bit of basic biochemistry. There are three major "macronutrients" required for human nutrition--carbohydrates (sugars), lipids (fats), and proteins. All of these are absorbed through the intestine whenever you eat. Macronutrients are then delivered to the liver or various cells of the body that can use them. Carbohydrates are easy; the body breaks them down into smaller units and uses them to produce ATP, a small molecule that is the primary source of energy for the body at the cellular level.

Proteins and fats cannot be used directly by most cells. Instead, the liver processes them into more readily useful forms. Some proteins can be converted into glucose, the most basic (and preferred) form of fuel for body systems, especially neurons. Fat metabolism is more complicated and involves many steps that ultimately culminate in the release of free fatty acids; these are also usable as fuel by many body systems.

If you eat too much of anything, be it proteins, carbohydrates, or fats, the body is remarkably efficient at storing the excess energy produced. The most energy-dense form of stored energy is fat; fats produce the most energy (in calories) per gram. This fat winds up getting stored throughout the body as a reserve for times when food sources are scarce. Each pound of fat on your body represents a total stored reserve of 3,500 calories. Yum!

I've heard it mistakenly stated that you "can't get fat" eating a high-protein diet because "carbs make you fat" or, more obviously, "fat makes you fat," but this is completely false. Your body can (and will) make fat out of anything the liver can get its...um...lobes on.

What does this have to do with Alli?

Alli is not actually absorbed into the bloodstream. Instead, it floats around in the intestines and binds to fat molecules, preventing those from being absorbed. If your body doesn't absorb the fat molecules, it can't process them--in a sense, it's like you never ate them in the first place. Alli binds an average of 25% of consumed dietary fats, potentially reducing caloric intake from a fatty meal significantly.

Problem: Alli is not magic. It cannot break the laws of physics and destroy matter (and I suspect converting fats to energy in your intestine would have odd effects, were it possible). If you don't absorb the fats, they still have to go somewhere. Since they're already 3/4 of the way through your digestive tract, and getting the whole system to flow in reverse is both very unpleasant and very difficult, I'll let you think about it on your own for a second.

A funny aside: The makers of Alli recommend that you not wear light-colored pants while taking it.

I personally like to think of Alli as "negative reinforcement." Operant conditioning is basic psychology. Continuously eat fatty meals on Alli and you're going to suffer chronically oily stools. You're either going to learn to control your dietary fat intake or you're going to throw away your Alli.

This isn't to say that Alli is bad. As part of a comprehensive diet and exercise plan, it will help you lose more weight, even if it's only a few extra pounds. But the reason Alli can get FDA approval, aside from the fact that it's been subjected to more rigorous clinical trials, is that Alli doesn't claim to be magic. "Eat all you want and still lose weight!" "Melt fat away while you sleep!" Due to loose regulations, dietary supplement manufacturers make these kinds of claims all the time. But the makers of Alli had to be realistic about the potential benefits of their drug to get it approved. This isn't a bad thing. It's what we should expect from all drug and supplement manufacturers--indeed, it's what should be legally required.

Anyway. Now Europeans can experience the thrill of Alli without a doctor's prescription!

...just remember to wear dark pants.