Do you remember the old nursery rhyme? Jack Sprat would eat no fat, his wife would eat no lean, and between them, they licked the platter clean. Was Mrs. Sprat on the Atkins low-carbohydrate/high-fat diet? Was she filling her platter with high cholesterol, high-fat proteins such as bacon, sausage, egg yolks and cheese? If so, poor Mrs. Sprat may now be in a cardiac intensive care unit recovering from a heart attack.
According to a Greek research team who followed the health and lifestyle of over 43,000 Swedish women for more than 15 years, increasing protein intake and decreasing carbohydrate consumption is associated with a significant increase in heart disease, stroke, and peripheral arterial disease along with other cardiovascular problems. This study was reported online in the British Medical Journal. The accompanying journal editorial suggested that the low-carbohydrate diet probably contributed to an inadequate consumption of whole grains, fruits, and starchy vegetables, and the lack of fiber, vitamins and minerals may have been associated with heart disease.
Were the women on the high-protein, low-carbohydrate food regimen attempting to lose weight or maintain their weight loss? The study doesn’t tell us. But the decade-long popularity of shunning carbohydrates in favor of high fat protein may have been the motivation for abandoning grains, potatoes and bread.
Some very recent evidence suggests that there may be a slight advantage to following a high-protein, low-carbohydrate diet in order to lose weight. David Ludwig, a director of an obesity prevention center at Childrens’ Hospital Boston, was an author of a study comparing different diets on energy expenditure. In this study, published in the Journal of the American Medical Association, eating a high-protein diet boosted energy expenditure by about 300 calories a day (slightly less than the calories in a bagel).
But before feeding your potatoes and bread crumbs to the local birds in your neighborhood, consider another finding of this study. The increase in protein consumption also caused the stress hormone cortisol to increase along with another chemical, CRP, that increases with inflammation. The increase in these two substances is associated with a bigger risk of developing both heart disease and diabetes. Might this have been the reason for the higher incidence of cardiovascular disease among the Swedish women who consumed a high-protein diet? Does a high-protein diet leave you thin but at risk for dying young?
Mrs. Sprat, now thin and at risk for heart disease, according to both of these studies, may also be suffering from a persistent case of grouchiness. Our studies, published several years ago in the Journal of Nutrition, found the “good mood” chemical, serotonin, decreased in the brains of laboratory rats when they were denied carbohydrates. Diets that drastically decrease starchy carbohydrates and limit their intake to fruits and non-starchy vegetables limit the ability of the brain to produce new serotonin. Women’s brains have less serotonin than men’s brains to start out with and a low carbohydrate diet may leave Mrs. Sprat vulnerable to the bad moods associated with too little serotonin, which include anger, fatigue, confusion, tension and depression.(Poor Mr. Sprat).
Unfortunately the study of Swedish women did not report the prevalence of depression, severe premenstrual syndrome or winter depression, so we don’t know whether those women following low-carbohydrate/high-protein diets were more prone to these serotonin-related mood disturbances than their carbohydrate eating peers. But both the Swedish and Boston studies do point out that dietary changes adopted as a means of losing weight might have unexpected and unintended health risks.
The scientific literature is filled with studies comparing diet X to diet Y, and the Internet is filled with numerous testimonials to a particular way of losing weight. In the end none of this is very helpful to someone who must lost 50 or more pounds and simply can’t lose it or lose it and keep it off. Weight loss has to meet the dieter’s individual nutritional and psychological needs, not just for the 12 or 16 weeks of dieting but permanently. We can read the results of the Swedish women’s study or the David Ludwig study but still not know how to use this information for our own weight-loss objectives.
Perhaps the way to begin is to figure out why we eat more than we need and why we don’t exercise as much as we should. The answers are not to be found in high- fat versus low-fat diets, raw versus cooked food, walking versus yoga or weight lifting versus resistance bands. Why was Mrs. Sprat eating only fat? Was she unhappy with her husband and consoled herself with bacon and cheese? Did she exercise afterward or did the fat make her too lethargic to expend energy on anything other than eating?
All of us have our own reasons for overeating and under exercising. Figuring out what they are and getting help in changing them is the key to successful weight loss and a healthy life-even for Mrs. Sprat.