Adaptive Thermogenesis

I decided to peruse the International Journal of Obesity to find an interesting article. Most of the articles looked at things from a more macroscopic vantage point than I am used to (not so much on the protein or atomic level) highlighting the necessity for more research later more in depth. Better protein chemistry could later lead to more drugs. However, there was plenty that looked interesting. I choose the article, "Adaptive thermogenesis can make a difference in the ability of obese individuals to lose body weight" by A. Tremblay et al. First we should define thermogenesis. Originally thermogenesis related to the energy expenditure related to when an organism heats its body. This is accomplished largely through stimulation of norepinephrine which stimulates the betaadrenergic receptor and finally lipases to feed fatty acids into energy expenditure. Caffeine, ephedrine, and green tea are all known to stimulate this process. This paper explores one important observation: why do people that were fat and have lost weight show a decrease in the ability to loose weight (in the form of adaptive thermogenesis). One hypothesis is that adaptive thermogeneis (a decrease in thermogenesis) is a means to protect your body from depleting its energy stores (in the form of fat). Seems reasonable from an evolutionary stand point. Obese individuals that have lost weight show a decrease in leptin plasma levels which could contribute to the decrease. Another hypothesis is that pollutants interfere with thyroid function, a hormonal control over energy expenditure. Interestingly, probiotics may have a role. Mice that have lactobacillus (releasing conjugated linoleic acid)showed increased energy expenditure. Dietary calcium was also shown to increase thermogenesis, by means of inhibiting lipogensis and increasing lipolysis. The biochemical pathways associated with increased thermogeneis associated with calcium intake seemed weak to me (not necessarily untrue, just not well explained). One depressing factor described by the paper is that 80% of people that loose weight eventually go back to pre-weight loss levels. Also, people that have lost weight have an increased desire to eat food and have a more difficult time reaching satiety, The most direct conclusion towards weight loss recommended by the authors is the administration of leptin to people that have lost weight. I need to make a future post on leptin as it is extremely important in the obesity epidemic.

 Today I weighed in at 132.2 kg. My weight really seems to be bouncing around a lot. I had the usual eggs .and cheese for breaky. Sausages for lunch. Taco salad for dinner