Do colder temperatures help you lose weight?

With much of the country in the throes of the polar vortex, there is a concern about peoples' well-being in such cold weather. However a different perspective is that moderate cold may not be such a bad thing. Some say you should turn down the heat in your home because colder temperatures help you lose weight from shivering and other responses to keep the body warm. Is this true or is this some old wives' tale?

The answer appears to be yes, but only modestly so. A recent paper offers new data on the topic. In the study, 17 individuals (9 women and 8 men, average age ~ 23) were subjected to mild cold conditions (15 - 16 ^oC or ~60 ^oF) for 6 hours.  Energy expenditure was measured by indirect calorimetry (i.e. by measuring oxygen consumption or carbon dioxide production). The basal metabolic rate (BMR = energy expended at rest) was measured in the cold versus at a neutral temperature (22 ^oF or 71.6 ^oC).

Let's look at the numbers.

The BMR at the neutral temperature was 1480 calories/day (women) and 1815 calories/day (men); at the colder temperatures the BMR was 1650 calories/day and 2030 calories/day. Thus, the increase caused by the moderate cold was approximately 200 calories when extrapolated to 24 hours. The typical man will consume 2600 calories/day and the typical woman consumes 2000 calories/day. In addition to your BMR, a person burns calories by active movement (e.g. walking).

As a reference for the magnitude of the 200 calories, one can examine the caloric content for some typical food items:

1. A chocolate chip cookie = 78 calories
2. Can of soda = 182 calories
3. Slice of pizza = 285 calories

These values can be found by Googling the food name, and Google now supplies the calorie total along with other nutritional information.

In addition, one can compare the 200 calories to moderate or vigorous exercise. Typical moderate exercise (e.g moderate or brisk walking, doubles tennis, yoga, or sex) consumes about 5 calories/minute. Typical vigorous exercise (e.g. jogging or running, step aerobics, performing jumping jacks) consumes about 10 calories/minute.

So yes, moderate cold can help you lose weight, but the effect is relatively minor. The 200 calories lost from spending 24 hours in the cold can be equaled by foregoing one slice of pizza, or by spending 40 minutes walking or 20 minutes jogging, and then keeping yourself warm for the rest of the day.

Figure 1. Yes cold weather can help you lose weight but exercise or proper dieting is more effective.