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SETTING THE RECORD STRAIGHT
January 16, 2004
Source: www.wheatfoods.org
New Year's resolutions to lose weight and get in shape are all the rage at this time of year, and 2004 is no exception. However, fad diets which make quick weight loss claims, limit food group recommendations, and set rigid menus are NOT a healthy way to start the new year. These diets make grand promises, but what's the real story behind the science?
THE LATEST FAD DIET CLAIM
To truly evaluate which diets are the best for long-term health and weight management, take a closer look at the science behind them. Research shows carbohydrates are essential for a healthy diet and for managing waistlines. A few things for consumers to consider before jumping on the low-carb bandwagon:
Validity of High-Fat, Low-Carbohydrate Diet Research Questioned. Tufts University recently presented research stating the popular Atkins diet's weight loss claims may not be as legitimate as low-carb diet promoters would like Americans to believe. A study presented at the American Heart Association's (AHA) annual Scientific Sessions claimed, " … people who followed the Atkins plan for six months - eating some 60 percent of their calories as fat, with 30 percent as protein, and just 10 percent as carbohydrate - lost an average of 31 pounds. A similar group who ate a heart-healthy diet - with 30 percent of calories as fat, 18 percent as protein, and 51 percent as carbohydrate - lost only 20 pounds." Good-bye bread, hello bacon? Not exactly! There are many questions about the Atkins plan that remain unanswered. First, there is the issue of just where the 11 extra pounds lost came from. Part of the difference is the fact that Atkins followers ate 100 fewer calories a day than the other dieters. Over six months, that adds up to about five pounds. It is well known that diets that drastically limit entire food groups, such as the grain group and many fruits and vegetables, make eating monotonous and uninteresting. As for the rest of the weight loss, a fair amount comes from water losses. The more you restrict calories, the more compounds called ketone bodies are formed - and must be excreted in the urine. Water output also increases with high-protein diets in particular because breakdown of the excess protein leaves a lot of nitrogen in the body that must be excreted in the urine. But water is not what you want to lose - it is fat loss that counts. To make the comparison of the two diets fuzzier still, the study has not been published in a peer-reviewed journal. Other scientists have not had the chance to scrutinize its methodology and see if there were any flaws that could have influenced results. For sustained weight loss and long-term cardiovascular health, the AHA recommends a daily dietary balance of about 15 percent of calories from protein, 30 percent from fat, and 55 percent from carbohydrates - combined with regular exercise, such as 30 minutes of brisk walking every day. (Source: "Tufts University Health & Nutrition Letter," January 2003; American Heart Association)
Low-Carbohydrate Diets May Increase Risk of Kidney Stones, Bone Loss. Low-carbohydrate diets may increase the risk of kidney stones and bone loss by causing a reduction in calcium metabolism - and the process starts after just two weeks. Researchers recruited 10 people who wanted to lose weight and asked them to follow the Atkins diet. For two weeks, volunteers followed the Atkins "induction" plan, eating an average of 19 grams of carbohydrates a day and as much protein (and fat) as they wanted. They then switched to the more liberal, still low-carbohydrate, "maintenance" plan for four weeks. Scientists found the subjects' urine had become markedly more acidic, and there was a "striking increase" in the amount of acid their kidneys had to handle. The more acidic the urine (a result of both the high animal protein and very low-carbohydrate content of the diets), the more likely kidney stones are to form. An outflow of excess acid also promotes excretion of calcium, throwing the body into a deficit that could lead to bone loss. (Source:
Shalini T. Reddy, Chia-Ying Wang, Khashayar Sakhaee, Linda Brinkley, Charles Y.C. Pak. "Effect of low-carbohydrate, high-protein diets on acid-base balance, stone-forming propensity, and calcium metabolism." American Journal of Kidney Disease 40, 2:265-74, 2002
Study Shows Adults on High-Carbohydrate Diets Less Likely to Be Overweight.
A U.S. Department of Agriculture (USDA) study showed participants on high-carbohydrate diets consumed 300 fewer calories per day than those on very low-carbohydrate diets. The study, based
on food intake data from 10,014 adults across the United States, also showed adults who ate
high-carbohydrate diets were more likely to be in the normal weight range, with the lowest average body-mass index. Additionally, high-carbohydrate diets were indicated to be more nutritious than low-carbohydrate diets, providing greater intake of vitamins A, C, carotene, and folate, and the minerals calcium, magnesium, and iron. (Source: USDA Agricultural Research Service, Journal of the American College of Nutrition, June 2002)
As with most fad diets, little is known about the long-term effects of high-fat, low-carb regimens. And the fact is most dieters don't stick with them long enough to find out.
THE BOTTOM LINE
Diets - whether low-carb or not - are difficult to maintain. Simple portion control, using the Food Guide Pyramid* to maintain a balance of all food groups, and exercise are more successful than dieting - and scientifically proven to be safer, healthier, and more fulfilling as a long-term approach. For a look at scientifically valid successful weight loss, consider the findings of researchers at the University of Colorado, the University of Pittsburgh, and Brown University. These researchers routinely collected data on a group of people comprising the National Weight Control Registry (NWCR). To be eligible for inclusion in the registry, an individual has to have lost a minimum of 30 pounds (13.6 kg) and maintained the weight loss a minimum of one year. On average, the 3,000+ registrants have lost 71 pounds (32.4 kg) and kept the weight off for more than six years. According to researchers, strategies previously identified that contribute to their success are: eating a low-fat, high-carbohydrate diet; monitoring food intake and body weight; and maintaining high levels of physical activity. (Source: Wyatt H, Grunwald G, Mosca C, et al.
"Long-term weight loss and breakfast in subjects in the National Weight Control Registry." Obesity Research 10:78-82, 2002)
*Critics of managing weight using the Food Guide Pyramid who blame the obesity epidemic on the foods emphasized (such as grains) are missing some facts. The Centers for Disease Control's latest statistic of
65 percent of Americans are overweight or obese runs in sharp contrast to the less than six percent of Americans who follow the Pyramid.
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For interviews with nutrition experts who can recommend healthful, long-term weight management plans, please contact Julie Balmer at (816) 512-2293 or JoDee George at (816) 512-2420.
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