Low-carb diets are all the rage, but are they good for you?
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Ron Hudson, a 56-year-old salesman, looked at me in disbelief. Had he actually just heard those words from my mouth? “You have diabetes,” I told him, “and the time has come for you to do something about it.” At 396 pounds, Ron knew he needed to get his lifelong weight problem under control. However, every diet plan he tried met with inevitable failure, because his motivation to succeed was not strong enough to overcome his cravings for snacks. His desk drawer at work was filled with unhealthy treats: doughnuts, cakes and king-size candy bars. Ron knew the time had come to make a drastic change. Not only did he sink into depression whenever he thought of buying new clothes, but he had already lost several family members to the complications of diabetes. Finally, last Memorial Day, Hudson committed himself to a diet plan that some may consider extreme: he stopped eating carbohydrates.
To eat or not to eat carbohydrates, that is the question. Once hailed as a necessary part of all meals, the backlash against carbohydrates (sugarlike molecules) has been immense. With the popularization of diet-plan books such as Atkins for Life, Sugar Busters!, The South Beach Diet and The Fat Flush Plan, one is left to wonder if there is anything safe to eat anymore. Surely, with soaring obesity rates and ever-increasing numbers of childhood diabetics, signs point to a dangerous trend in the American lifestyle. But what can be made of all the claims of low-carb diets? How do they compare with the more traditional way of eating, with a mix of all the food groups, that is recommended by the USDA Food Guide Pyramid?
Low-carbohydrate diets didn’t just start in the past decade. The Atkins diet has been around for 30 years, and scientists have noted the benefits of reducing certain types of foods in the diet for a century or more. However, never before has such an emphasis been placed on the nutritional value of what people eat, and never has there been such confusing, seemingly contradictory information. Nutrition experts have to go back to the drawing board and reformulate a plan based on current scientific evidence and research trials, challenging the findings of a mere decade ago.
The basis of all low-carbohydrate diets is that, by eating less of the immediate sources of fuel, the body is forced to burn its stores of fat, thus leading to weight loss. Research has shown that keeping a diet too low in carbohydrates does increase the risk of episodes of hypoglycemia, or low blood sugar. Low blood sugar can result in dizziness, fatigue, nausea and vomiting. In rare cases, hypoglycemia can lead to a loss of consciousness, which may require emergency medical care.
However, most of these diet plans do not recommend following the drastic cuts in carbohydrates for an extended period of time. The average American diet includes 300-350 grams of carbohydrates. The Atkins diet plan suggests an initial two-week period when the daily intake of carbohydrates does not exceed 20 grams. Over time, this number is increased, balancing the effects of more carbohydrates with the body’s need for fuel.
Some newer research has lead to the concept of the glycemic index, a measure of how fast carbohydrates are absorbed into the body and digested down into molecules of sugar. Once circulating in the blood, sugar promotes the production of insulin by the pancreas. Higher levels lead to increasing demands for insulin to help push the sugar into the body’s cells. This increase may lead to higher rates of atherosclerosis, and, over time, to insulin resistance, a precursor to diabetes. By lowering the amounts and types of foods with high glycemic “scores,” such as sweets, pastries, bread, white rice, etc., the burden of sudden fluctuations in insulin levels can be minimized over time. Lower levels of insulin also lead to higher levels of another hormone, glucagon, which regulates how the body breaks down its stores of fat for energy.
Do low-carb diets work? Two studies published last May in the New England Journal of Medicine presented the first-ever, randomized trials of a low-carbohydrate, high-protein, high-fat diet vs. a traditional, low-calorie, high-carbohydrate, low-fat diet. The first trial was performed at the Veteran’s Administration Hospital in Philadelphia. This study tested 79 people randomly assigned to either diet over a six-month period. The results showed that severely obese patients, with a high prevalence of diabetes, lost more weight during the study period on a low-carbohydrate diet than those on a calorie-restricted, low-fat diet. Cholesterol levels improved, with greater decreases in the triglycerides in the group following the low-carbohydrate model. However, there were only a small number of people enrolled in this study, and the benefits beyond the six-month study trial were not assessed.
In the same issue of the New England Journal of Medicine, research from the University of Pennsylvania reported on a one-year study that showed slightly different results. That study assigned 63 individuals to either an Atkins-like diet or a conventional low-fat, high-carbohydrate diet. Blood sugar, cholesterol and weight were all measured throughout the study. Initially, the low-carbohydrate dieters lost more weight and had improvements in their blood tests sooner than the low-fat dieters. However, at one year, the difference between the groups was not statistically significant—the groups basically reached the same amount of weight loss over time. Atkins dieters were shown to have the most improvements in their cholesterol values, but whether this benefit was permanent remains to be seen. The final tally: the pounds lost were the same. The real question is simply, who will keep the weight off over time?
Concerns have been raised regarding the potential harm of a high-protein, high-fat diet. Those with a history of gout (a metabolic problem that causes painful arthritis in certain joints) are warned about the potential for recurrences while eating large amounts of protein. The long-term effects of high-protein diets on the kidneys are not yet known. (Diets higher in protein may challenge the kidneys to process more protein than they can.) Followers of high-protein diets may be putting themselves at risk, but for what, the medical community just does not know. More research must be done in order to determine the long-term effects of low-carbohydrate diets.