You know you're a chemical engineer when....

2003-02-27 - 12:40 p.m.

The problem with the world of nutrition is that there is SO much false information out there that it's rediculous! Sara Jane, you're quite correct in your assessment of the importance of certain fats and the dangers that processed sugars and carbohydrates have on the body. Yet, most 'weight conscious' people will often choose gummy bears as a snack over, say, almonds. Why? Because the gummy bears have no fat. It's easier to burn off calories than to get rid of fat. Oh, the ignorance!

Here's the issue when it comes to fueling your body. A calorie is a calorie is a calorie. Whether you get your calories from a fat free source or a full fat source, you're still putting the same amount of energy into your body, and it will be processed, from a thermodynamic perspective, in the same way.

However, it's the actual stuff that's the problem. The sugar will impact your body in different ways than the oils. They have different nutritional benefits and problems.

One of my favorite diet crazes is to drink apple cider vinegar after a fatty meal. Why? Because the strong acid will burn up the fat. Once it's all burnt, the body can't process it and it can't get deposited onto your butt. Or so the story goes.

Umm, let's think about that for a second. First of all, acids and olefins don't mix without the aid of a surfactant or some other such emulsifier (if you don't believe me, just turn to your oil and vinegar salad dressing). If two things don't mix, then they don't react. So this magical 'burning' these so called experts talk about can't even happen (well assuming they're calling it a chemical reaction, rather than a magic trick). But okay, so let's assume you ate something that acts as an emulsifier, and causes the apple cider vinegar to mix with these olefins in your tummy. Well, I bring you back to your salad dressing bottle. When you shake it, does the oil decompose? NO! Because acetic acid (vinegar) does not decompose olefins!

Even if you don't look at it from such a scientific perspective, everybody has heard of 'acid reflux'. Everybody knows your stomach has acid in it. Why add more? There's already some in there!

Another of my favorite diet myths is that you can spot work fat my doing certain exercises (for example doing sit ups to reduce tummy fat, leg lifts to shrink your bottom and thighs, etc.). Sorry folks, but it doesn't work that way. Again, I take you to chemistry (specifically, to thermodynamics).

First, let's talk about how fat burns. I'll put it in simple chemistry terms that anybody who took a chemistry class in college should be able to follow. Fat is a hydrocarbon and the 'burning' of fat occurs in what is called a combustion reaction. As your freshman chem book will tell you, in a combustion reaction, a hydrocarbon reacts with oxygen in an exothermic reaction to form carbon dioxide and water. It gives off energy in the process. It's sort of like your gas tank in your car.

The calories you eat everyday are like your gas tank, and the fat stored on your body is sort of like a resreve tank or something (I'd call it the gas station, but your refrigerator fits that description better).

So, when you exercise (or just exist), if your body requires more calories than you are consuming, then it will go to your reserves for fuel. Oxygen from your blood will diffuse into the fat cells, react, and produce energy. Carbon dioxide and water go into your blood stream and are breathed out (conveniently, you breathe out carbon dioxide and water all the time anyway, it's not an issue).

So that doesn't really answer why you can't 'spot work', though. Well, it sort of does. I mean, the oxygen doesn't attact the fat in the area where there's motion, it attacks fat where it is best for your body (determined by genetics, I'm afraid).

Let's compare that to what happens when you do spot work. In short, this is for building muscle. How does that work? Well, it's sort of like when you get a callus. When you use a muscle repeatedly to the point of fatigue (when it starts to hurt and you can't do anymore), you are overworking it and tearing it apart. This causes pain. The muscle then heals itself stronger (I'm not going to get into the chemistry of that process, but it involves lots of water), that way it could endure the same amount of work next time. You then exercise to fatigue again, and the cycle continues. This is all why stretching and taking a day off in between working muscle groups is so important. You want the muscle to grow back correctly.

Thus, muscle building and fat burning are two different processes. They are pretty much unconnected. Well, not entirely. Because when you work your muscles you burn calories to do so, which in turn will burn fat. And muscle requires a good amount of energy to use and maintain, which increases your metabolic rate, which makes you burn more fat. But the fat on top of big muscle does not necessarily burn faster than fat not on top of small muscle.

I was also going to get into 'when you eat' myths, but I've been at this long enough. But I should get back to work, and there's some drama going on right now (broken equipment, really expensive equipment, it's a REALLY big deal).