Tuesday, March 4, 2008

Sugar Substitutes and Gaining Weight

I've posted a link below to an article that was recently in Time, Inc. magazine. Researchers at Purdue University studying Behavioral Neuroscience have conducted a series of tests with rats that suggest eating high levels of sugar substitute "aspartame" (Sweet n Low) results in greater weight gain than rats that eat diets with glucose, a naturally occurring sugar in nature. While the results seem counter-intuitive, they make good sense.

The thesis is that the rats given a sugar substitute gained more weight because they ate more food. Why did they eat more food? Well all else being equal, the researchers believe that the body, when hungry and in need of energy, wants something chemically equivalent to nature's natural source of energy, which is glucose. If you give your body a sugar substitute, all you are really do is provide the taste receptors on your tongue with something that tastes sweet. But biochemically, the body says "Wow, that tasted sweet, but you know what, I really still need energy, so I'm going to keep stuffing my face till I get some glucose."

Therefore, the researchers contend that the weight gain isn't directly caused by the artificial sweetener, but rather, gaining weight is indirectly caused by the calories your body takes in due to its "search" for real sugar/energy. It's the best theory I've seen so far. Last I checked, aspartame is a dipeptide, so breaking down a dipeptide takes more energy than breaking down sugar to utilize a monosaccharide like glucose for energy. (Sugar is a disaccharide made up of glucose and fructose monosaccharides linked together.) Nature is efficient, so the body will always prefer glucose to everything else for energy. And all those drinks that are loaded with high fructose corn syrup? These too are less favorable from a "natural energy source" perspective than glucose, but certainly more natural than the aspartames and other substitutes of the world. But fructose in concentrated form is still not that good for you, relatively speaking.

You know, Ben Franklin defined insanity as doing something over and over, thinking things will change, yet your reptitive actions don't produce the desired outcome. Eating sugar substitutes to lose weight is the biochemical version of insanity, if this research is marginally true.

The final note in this article is a good reminder that, while evidence might argue for eating natural sugar vs. a substitute, in excess, diseases like obesity and diabetes are still possible if you lack self restraint. Choosing to binge on sugar vs. a sugar substitute are not mutually exclusive...but diabetes and obesity are certainly a zero sum game.

Link to Article in Time

Link to Paper by Dr. Susan Swithers of Purdue