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By Dave DiFabio
Have you heard of the hormones Ghrelin and Leptin? These are hormones that occur naturally in the body. Basically, they dictate your genetic set-point in terms of body weight. Thanks to the human genome project and studies involving gastric bypass patients, it is thought that everyone is pre-programmed to be a certain body weight. This programmed system works on a negative feedback loop; similar to a thermostat. Let's say you set the thermostat in your house for 70 degrees and it's 90 degrees outside. The air-conditioner will pump cold air till the house is at 70 degrees instead of 90 degrees like it is outside. The thermostat will sense the cold air. Once it gets to 70 the air-conditioner will stop producing cold air for a while until the temp rises above 70 again. Then it will produce more cold air until 70 is achieved again. Basically, cold air will limit the production of more cold air in order to keep homeostasis at the limit of 70 degrees to which the thermostat is set. This cycle would continue until you either adjust the thermostat or the environment changes.
Ok, back to the hormones. Leptin is an appetite suppressant. Ghrelin is an appetite stimulant, which also increases levels of growth hormone. Now let's say your body weight thermostat is set to 250 lbs. Leptin and Ghrelin control the thermostat and limit each other to keep homeostasis at 250 lbs. Let's say you start dieting and you lose a couple lbs and drop below 250. Guess what happens? Ghrelin goes up to stimulate the appetite, which in turn lowers Leptin (an appetite suppressant). Lower Leptin levels would also cause hunger. That's not good if you're trying to lose weight. This process would continue until weight is regained bringing levels back up to 250. Then Leptin would again increase and Ghrelin would decrease thus stabilizing hunger pangs and weight. If you've tried to lose weight by dieting alone, you've certainly experienced this phenomenon. As you lose more and more weight it becomes harder and harder to lose more weight, due to increasing hunger.
So what's the solution? One strategy is to adjust the thermostat. Gene therapy technology is still in its infancy. However if you could somehow modify and/or delete the genes that make Leptin and/or Ghrelin you could definitely adjust the thermostat up or down. I wouldn't hold your breath just yet. Instead of directly attacking the genes, pharmaceutical companies are researching compounds that can block the effects of Ghrelin or mediate the effects of Leptin. Again, don't hold your breath just yet. Both scenarios scream of side-effects. Another way to adjust the thermostat is with gastric bypass surgery. Not only does it physically limit how much food you can eat in one sitting, but it also reduces the amount of Ghrelin your body produces. The pros and cons of this procedure is another discussion in itself. One of my clients can certainly attest that it's not a shortcut. It requires a huge commitment to change before and after surgery.
So what's left? Change the environment. First don't starve yourself or deprive yourself. This will only shock the thermostat and not in a good way. Ghrelin will kick into high gear. Second we can try to "fool" the body into thinking it should be leaner. It's no secret that resistance training can increase lean muscle mass. Think of muscle as a highly metabolically active, food-burning furnace. If you can add a little muscle with weight training you will then increase your metabolic rate. This means you'll burn more calories throughout the day not just while you're exercising. Mix in some interval training and a balanced diet and you can "adjust" the thermostat enough to squeeze into those skinny jeans.
Till next time.... Train Like You Play & Play Like You Train
Dave DiFabio MA, CSCS, USAW
Owner/Strength & Conditioning Coach - Team Speed Fitness LLC
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