Losing weight leaves couple feeling a little cold

Q. My husband and I are trying to get in better shape and lose some of that weight that has crept into our clothes over the years. Aside from the obvious, we are concerned because simple physical tasks take the wind out of us more than they used to. The reason I am writing is that as we are cutting back on our food and managing to drop some weight, but we are both quite cold, especially at night. Aside from wearing fleece long johns, is there anything we can do to change this? We want to continue, but the chills are a real pain.

J.B., Milwaukee, Wis.

A. Congratulations on your decision. The fact that you are making it as a couple will make it that much easier to achieve your goals.

One caveat before I proceed: I don't know your age or health status, but if there are any issues of concern, it is always best to touch base with your doctor.

While the decision to get in shape began as a conscious -- and very intelligent -- choice, it helps to appreciate that it's coming as a complete surprise to your body. Our many control systems can't tell the difference between a diet and a famine. You and your husband know what you have in mind, but your bodies are not in the loop. They assume that scarcity has become the new status quo.

The body's sacred currency is its store of energy, and it equates excess energy (i.e., the weight that crept into your clothes) with better odds for survival. You would think that the body would be pleased to get down to its fighting weight, but that works about as well as asking a miser to share the wealth.

How the body adapts to caloric deprivation depends on the difference between the number of calories taken in and the number burned as your daily cost of living.

Typical adaptations include a slower metabolic rate, lower body temperature and other actions that leave you feeling short of energy and needing sleep (another form of calorie conservation).

A study in the American Journal of Clinical Nutrition (February 1992) looked at healthy, overweight premenopausal women. Their diet went from the normal level of 2,200 calories per day down to 800 calories per day. While on the diet, the scientists took periodic measurements of nighttime body temperature and sleep patterns.

The study reported a significant drop in nighttime body temperature, but the quality of the dieters' sleep was also affected. While on the diet, it took longer for the women to fall asleep, and they had significantly less slow-wave sleep, the type associated with the repair and growth of body tissues. These types of metabolic slowdowns have been reported for men and in other age groups.

All this underscores that a successful long-term strategy needs to rely on more than a reduction in calories. A daily exercise component may provide an answer. As we have learned, the body does not like to waste energy. Muscle is metabolically active: It burns calories and gives off heat even while at rest. The body, however, keeps an amount of muscle sufficient only to maintain the status quo.

A regular routine of weight-bearing exercise can build your lean body mass, and those muscles can help compensate, in part, for the decreased energy expenditure resulting from weight loss. All this can help you cast off that unwanted resident in your clothes.

Please understand that success means committing to this as a long-term affair, which means reducing your caloric intake just enough to promote slow, steady weight loss. Having both of you working together can make the difference. Snuggle up, stay warm and let me know how things progress.