I’ve known for a while now that exposure to cold climates increases metabolism. I found this journal article (http://jap.physiology.org/content/93/1/77.full.pdf) that proves my hypothesis. Here’s the summary:
Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids
Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids. J Appl Physiol 93: 77–84, 2002. First published March 1, 2002; 10.1152/japplphysiol.00773.2001.—The relative roles of circulatory glucose, muscle glycogen, and lipids in shivering thermogenesis are unclear. Using a combination of indirect calorimetry and stable isotope methodology ([U- 13C]glucose ingestion), we have quantified the oxidation rates of these substrates in men acutely exposed to cold for 2 h (liquid conditioned suit perfused with 10°C water). Cold exposure stimulated heat production by 2.6-fold and increased the oxidation of plasma glucose from 39.4 ± 2.4 to 93.9 ± 5.5 mg/min (+138%), of muscle glycogen from 126.6 ± 7.8 to 264.2 ± 36.9 mg glucosyl units/min (+109%), and of lipids from 46.9 ± 3.2 to 176.5 ± 17.3 mg/min (+376%). Despite the observed increase in plasma glucose oxidation, this fuel only supplied 10% of the energy for heat generation. The major source of carbohydrate was muscle glycogen (75% of all glucose oxidized), and lipids produced as much heat as all other fuels combined. During prolonged, low-intensity shivering, we conclude that total heat production is unequally shared among lipids (50%), muscle glycogen (30%), plasma glucose (10%), and proteins (10%). Therefore, future research should focus on lipids and muscle glycogen that provide most of the energy for heat production.
There’s a lot of math and jargon in there but in a nutshell; they put a few guys in suits that maintain 10°C or 50°F and measured the amount of energy their bodies used to maintain a core temperature of 98.6°F for two hours. The results are remarkable and very useful for those of us with a few extra pounds to lose. The men in the experiment burned 376% more fat wearing the cold suit versus sitting in an 80°F room.
Needless to say, I’ve been using this information to trim the fat. I got lazy when it started getting dark at 5:30 and started eating like crap. On New Years Day, however, I entered a Biggest Loser competition with my family members. I’ve been taking 30 minute walks in jeans, a hat, gloves and a Tshirt. It’s semi-painful, but I believe it is working.