How Weight Loss Supplements Work

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how weight loss supplements work

What are the mechanisms thru which weight loss supplements work?  This isnt an academic question because you have to understand how these supplements work in order to make good purchasing decisions.    In the recent article, a calorie is a calorie, it was pointed out that weight loss is determined by the physics of thermodynamics which we understand very well.  Only “calories in and calories out” determine weight loss/gain, nothing else.  Calories (energy) enters the body thru food/beverage and leaves the body as work done (from lifting things and movement) or heat (conducted, convected or radiated). If more calories go in than leave, then you gain weight. If fewer calories go in than leave, then you lose weight.

All weight loss supplements work either by decreasing the energy intake or increasing the energy output, there are four basic ways this can occur:

  1. by suppressing appetite (decreasing energy input)
  2. by lowering digestion efficiency (decreasing energy input)
  3. by increasing activity level (increasing work output)
  4. by increasing heat output (increasing heat generated)

Most weight loss supplements contain stimulants like caffeine, ephedrine (not legal in USA), or DMAA (Methylhexanamine).   Stimulants help you lose weight because of factors 3 and 4 above – they make you more active and they make your temperature higher so you produce more heat.  Of course the mother of all “weight loss” drugs is the illegal and highly addictive substance crystal meth.  Both activity level and body heat production are thru the roof (3 and 4 above) and the appetite is suppressed as well, of course, most crystal meth users end up dead or in jail so its not a recommended product.  Back in the ’60s, amphetamines were widely used for weight loss.

Lowering digestion efficiency (#2 above) isnt very common in supplements but many weight loss tactics use this.  The healthiest way to use this is to consume fiber (ie vegetables) because fiber lowers digestion efficiency.  Lots of water taken with a meal also lowers the digestion efficiency.  Intentionally putting tapeworms in yourself is a way of lowering your digestion efficiency because basically the tapeworms are eating your food for you.  Some prescription drugs work in this way as well like Orlistat which works by preventing the fat from being digested.

Reducing appetite (#1 above) can be accomplished in many ways.  By making food taste bad or by making you feel more full than you really are two common ways.  You can do this yourself by eating healthy, bland, unsalted foods, and drinking lots of water … or you can take the prescription drug Qsymia.  There are a number of natural supplements reported to have some small appetite supressant effects and then perscription medications like appetite suppressant is phentermine.

Lets look at #4 again, increasing the heat output. The body needs to maintain 98.6 degrees Fahrenheit or thereabouts to stay alive and the healthy range is rather small – say 97 degrees to 101 degrees. Higher than 104 and brain damage can result. When you get too hot, your bodies thermal regulator kicks in and causes you to sweat. Sweating is a marvelous way to regulate temperature because when water goes from the liquid form (sweat) to the gaseous form (steamy stench), it draws a huge amount of heat out of your body. To burn lots of calories, some of these thermogenic weight reduction supplements stoke your metabolic furnace which raises your temperature causing your body to perspire more and generate lots of heat. How effective is sweat at removing heat from the body? Incredibly effective, lets look at an example. When you are really hot you can easily sweat 1/2 gallon in an hour. The heat of vaporization of water is 0.540 kCal/g so to evaporate 1892 grams of water (1/2 gallon) uses up 1892*540 = 1021 Calories. Thats a lot of calories in just one hour! Keeping the body warm enough and cool enough requires a lot of calories so anything you do to cause more heat to be generated has a big effect on the caloric energy balance. As an aside, IMO ice cube baths are not an effective means of losing weight because you cant stay in long enough without dying. Cold showers arent effective because the duration is too short to have any appreciable effect on the energy balance. On the other hand, swimming for an hour or two in cool lap-lane temperature water is an incredible way of losing weight because not only are you burning calories to swim (perform work) but you are burning calories to keep your body warm enough (generating heat).

Any weight loss supplement you can think of acts thru one of the above four mechanisms.  If you see something advertised, see which of the four it is.  If they don’t plainly fit into one of those categories and spout gibberish and throw around trademarked, made up words then don’t waste your money :)

If losing weight were as easy as taking a pill, we wouldn’t have an obesity epidemic!

There are no shortcuts, you have to exercise more and eat less.