Cold Baths for Weight Loss? A HealthCentral Explainer
If you were to look at the Amazon.com best- selling Kindle Books list, you'd find Six Weeks to OMG atop many of the health, fitness and dieting lists. Of course, everyone wants to be skinnier — and in six weeks — but one has to ask how this is possible. What does this book offer that others have not? We all know that a combination of diet and exercise is the most effective way to lose weight, but many of us also want to know some short cuts.
In an appearance on the Today show, author Venice A. Fulton — real name Paul Khanna, a British actor and personal trainer who holds a degree in sports science — described some of the tricks: skip breakfast, drink two cups of black coffee on an empty stomach and take a 15-minute cold bath every day.
What does a cold bath have to do with weight loss?
Khanna, in his TV appearance, claimed, "When your body gets in a cold bath — it hates that — it ramps up metabolism to keep you warm. Just like turning up the thermostat, those calories have to be from somewhere." He said that his book, and this tactic specifically, is for people who want to lose fat. By this logic, the body is forced to keep warm and burns fat in the process. He claims that a 15-minute bath in 68 or 59 degree water should suffice.
When accused of using "junk science," Khanna said the cold bath theory was supported by research from the New England Journal of Medicine and the Mayo Clinic.
What does the New England Journal of Medicine say?
In truth, Khanna has contorted the research a bit. The NEJM published a study in April 2009 that analyzed how healthy, overweight and obese men reacted to cold temperatures. Specifically, the research identified that "brown fat" — which is responsible for regulating body temperature and different from the fat responsible for weight gain and calorie storage — was burned when the body was in cold temperatures. Though fat was burned, burning brown fat doesn't really help reduce your gut. In fact, brown fat is often stored in the upper chest region of men — not normally a target for weight loss efforts.
However, this study did find that the overweight and obese men generally had less activity in their brown fat — less was burned to keep warm — indicating that cold temperatures could be a means for reducing their weight.
Does a cold bath boost metabolism?
There may also be some basis for the idea of using cold temperatures to boost metabolism. Research from Current Opinion in Clinical Nutrition and Metabolic Care found that those who showed a low metabolic response to cold had a higher propensity toward obesity. Though not necessarily validating the claims that metabolism is boosted in lower temperatures, the study did confirm that with non-obese people, there was a metabolic change when exposed to the cold.
_[SLIDESHOW: Nutrition: The Bar Minimum] _
The International Journal of Sports Medicine published a study in 1992, concluding, "Exposure to cold at rest shifts substrate utilization from mainly lipids at thermal neutrality to carbohydrates, representing the main fuel for shivering thermogenesis." Translation: your body burns carbs when it is cold and shivering. Ok, that's a small confirmation of Khanna's claims.
The Canadian Journal of Sport Sciences found that "repeated and prolonged moderate exercise in a cold environment creates an energy deficit that is satisfied by an increased metabolism of depot fat." This study also concluded that this response to cold was better developed in men than in women. However, the study did cite some concerning side effects to exercising in the cold, including ketonuria and less "yield" from the same amount of oxygen as compared to regular temperatures. This study, it should be noted, does not specify whether or not this "depot fat" is of the brown variety, which does not necessarily validate Khanna's claims.
Finally, to fully dispel the myth of the cold bath for weight loss, exercise physiologist Dr. Stacy Ingraham, quoted in an article for CBS 4: Minnesota, said that cold weather actually slows metabolism. "To burn the most calories, sauna and room temperature, not cold water immersion." In any event, limit the length of time to any cold ice baths to no more than 10 minutes.
Khanna is also taking heat for targeting his book at impressionable teenage girls. He denies this, but even the Huffington Post has gone on the offensive against Six Weeks to OMG, questioning, "Could ice-cold baths trigger eating disorders?"
In short: the science doesn't back this up. Cold baths won't necessarily help you lose weight.
Fulton, Venice A. (9 July 2012). "'Six Weeks to OMG': the diet book that's got people talking." TODAY books. Retrieved from http://today.msnbc.msn.com/id/48125530/ns/today-books/#.T_8vlJGfaSp.
Shephard, R.J. (1992). "Fat metabolism, exercise and the cold." Canadian Journal of Sport Sciences, 17(2), 83-90.
Vailerand, A.L., Jacobs, I. (1992). "Energy metabolism during cold exposure." International Journal of Sports Medicine, 13(S1), 191-193.
Van Marken, L., Daanen, H.A. (2003). "Cold-induced metabolism." Current Opinion in Clinical Nutrition and Metabolic Care, 6(4),469-475.
Vascellano, Frank. (1 March 2011). "The cold, hard truth: can ice baths help you lose weight?" CBS Minnesota. Retrieved from http://minnesota.cbslocal.com/2011/03/01/can-ice-baths-help-you-lose-weight/.
Van Marken, L., Vanhommerig, J., Smulders, N., Drossaerts, J., Kemerink, G., Bouvy, N., Schrauwen, P., Teule, G. (2009). "Cold-activated brown adipose tissue in healthy men." The New England Journal of Medicine, 360,1500-1508.