Gettysburg Medical Center
 The Clinical View
 by  P.E. Hoffsten, MD
 19 April 2006

THE VALUE OF CALORIE RESTRICTION

            Last week’s column was devoted to the basic diet our ancestors had.  It was pointed out that they had no access to concentrated sweets or salt.  Not pointed out was that they had to go hunt down or gather whatever they ate as opposed to dropping into the local grocery store and picking it off the shelf,  Thus, they had a built in fitness program in addition to calorie restriction.  The argument about the content and composition of what we eat continues to rage.  Diet books abound and are one of the leading sellers in book stores.  However, hard data showing what a given diet can do is relatively scarce.

            The Journal of the American Medical Association for April 5, 2006, has a very pertinent article on the effectiveness simply of calorie restriction.  Also, in this issue of the Journal of American Medical Association are the latest National Health and Nutrition Examination Survey (NHANES) data.  This survey that has been repeated every 4 to 6 years since the 1970’s shows that there is a continued increase in the incidence of obesity in our children.  Now 17% of our children qualify as obese.  The incidence of obesity in men increased substantially in the last six years and now fully one third of the male and the female population is obese.  This epidemic of excessive weight continues to foster diabetes, high blood pressure and high cholesterols causing the heart attacks, strokes and dementia problems that are so prevalent in our society today.

            Medical research continues to uncover markers that predict heart attack and stroke.  Specifically, we know that high blood pressure, diabetes, high blood cholesterol and cigarette smoking account for approximately 95% of all the heart attacks and strokes that occur in this country.  But there are other markers that have come to light in the past few many years including insulin levels, CRP levels, thyroid hormone levels and degradation products in our proteins and DNA.  Measuring all of these different markers is not done on a routine basis but was done on a recent study mentioned above in the Journal of the American Medical Association.

            Specifically, the authors of this study recruited 48 very overweight individuals.  They were divided into 4 groups.  One group of 12 was not asked to make any changes in their lifestyle or their diet.  They provided the control group.  A second group was provided a calorie restricted diet decreasing their calories by 25%.  A third group was told to restrict their calories to 12 ½% less but to increase their exercise daily by 12 ½% more.  The last group was given a very low calorie diet of only 900 calories per day until 15% of their body weight had been lost.  The result of what happened with these 4 groups is very interesting.

            The group on the 900 calorie diet lost 15% of their body weight in about 2 ½ months.  Their calorie intake was then adjusted to maintain that weight loss for the remainder of the 6 month study.

            The surprise was in the group that restricted their calories by 25% versus the group that increased their exercise by 12 ½% and decreased their diets by 12 ½%.  In fact, the group getting more exercise lost less weight than the group that had the greater calorie restriction.  The control group lost no significant amount of weight at all.

            The lesson from this study is that exercise is healthy but really plays relatively little part in a weight loss program.  I pointed out before that walking one mile burns 100 calories.  In order to lose a pound of fat, one has to walk 40 miles.  I have never met anybody that did this to lose weight. The real answer to weight loss is decreasing calories.

            The remainder of the study was devoted to changes in insulin secretion, blood sugars, blood pressures, and various perimeters of inflammation that are markers for heart disease.  All of the individuals who lost weight had an improvement in their markers for heart disease and stroke. The message is that you don’t need an extreme weight loss in order to benefit your blood vessels.

            I have never counted up the number of people who come to me at this time of year and tell me that winter has been hard on them.  They couldn’t exercise and they gained between six and ten pounds since last summer.  But now that the weather is nicer, they are going to get out and exercise again.  I am not disrespectful of what they say but I don’t believe a word of it.  The fact again demonstrated by this study is that weight loss requires calorie restriction.  It means eating less.  Exercise by itself is healthy but is not a pivotal part of a weight control program.  It is a cop out to say that a person gained weight because they couldn’t exercise in the winter.  The pivotal fact of weight loss is the person has to eat less.  The health benefits are huge.  Our ancestors from 10,000 years ago were adapted to calorie restriction imposed upon them by their environment.  That calorie restriction is not imposed by our environment at all.  On the contrary, we are encouraged to eat bigger, better, higher, deeper, further and more, for everything from burgers to pizza, candy bars, pie, and cake.  The healthy step for longevity that you can enjoy is reasonable calorie restriction and maintenance of body weight near the ideal level.

            Rule #1:  To lose weight a person has to eat less.

            Rule #2:  Exercise is healthy but plays little part in promoting weight loss in our day to day sedentary life style.

            Rule #3:  Reread rule #1.