A low-carbohydrate diet may help prepubescent girls avoid some risks associated with obesity, such as diabetes and heart disease, according to research from the University of Alabama at Birmingham.
A reduction in dietary carbohydrates improved various metabolic indicators in overweight African-American girls even in the absence of weight-loss, according to their findings published online Dec. 1, 2011, in the Journal of Pediatric Gastroenterology and Nutrition.
The research team placed 26 obese African-American girls ages 9-14 on one of two diets. One diet drew 43 percent of its calories from carbohydrates, and the other drew 57 percent of calories from carbohydrates. After five weeks, the lower-carb group showed a reduction in lipids, such as triglycerides and cholesterol, along with better glucose control and insulin response and an improvement in reproductive hormones.
“Our goal was to understand better the effects of a low- or high-carbohydrate diet on girls before puberty, an important time in a young girl’s physical development,” said Krista Casazza, Ph.D., R.D., an assistant professor in the Department of Nutrition Sciences in the UAB School of Health Professions and first author on the study. “There is evidence that the prepubescent years are vitally important for young girls in terms of body composition and the development of good bone density.”
Casazza says that a diet high in carbohydrates sets off a metabolic cascade of events, such as an increase in blood serum glucose and insulin and an increase of lipids. These events are associated with an elevated risk of obesity, with all of its implications of increased risk of heart disease, High cholesterol, high blood pressure and diabetes.
“Understanding the role carbohydrates play in children’s development is important,” Casazza says. “If we can decrease exposure to the risk factors for disease at an early age, perhaps we can reduce the cumulative risk associated with these diseases over time.”
Many promoters of dietary schemes would have us believe that a special substance or combination of foods will automatically result in weight reduction. That’s simply not true. To lose weight, you must eat less, or exercise more, or do both.
There are about 3,500 calories in a pound of body weight. To lose one pound a week, you must consume about 500 fewer calories per day than you metabolize. Most fad diets, if followed closely, will result in weight loss—as a result of caloric restriction. But they are usually too monotonous and are sometimes too dangerous for long-term use. Moreover, dieters who fail to adopt better exercise and eating habits will regain the lost weight—and possibly more. My advice to people who are considering a low-carbohydrate diet is not to try it on their own by reading a book but to seek supervision from a physician who can monitor what they do.
The most drastic way to reduce caloric intake is to stop eating completely. After a few days, body fats and proteins are metabolized to produce energy. The fats are broken down into fatty acids that can be used as fuel. In the absence of adequate carbohydrate, the fatty acids may be incompletely metabolized, yielding ketone bodies and thus ketosis. Prolonged fasting is unsafe, because it causes the body to begin to digest proteins from its muscles, heart, and other internal organs.
Low-carbohydrate diets also produce ketosis, but if properly designed, they enable the body’s nutritional needs to be met by dietary protein, dietary fat, stored body fat, and stored glycogen, so that body muscles are spared . As this “nutritional ketosis” begins, there is a diuretic (water loss) effect, leading the dieter to think that significant weight reduction is taking place. However, most of the early loss is water rather than fat; the lost water is regained quickly when if the dieter resumes eating carbohyrate (as would occur, for example, with a balanced diet). Appetite, often reduced during ketosis, also returns when a balanced diet is resumed. In the past, it was thought that patients restricted their caloric intake because the food restrictions made the low-carbohydrate diet monotonous. However, current theorists suggest that appetite reduction has a hormonal basis .
The most widely publicized low-carbohydrate diet has been the one advocated by the late Robert C. Atkins, M.D., of New York City. His 1972 book Dr. Atkins’ Diet Revolution sold millions of copies within the first two years. His 1992 update, Dr. Atkins’ New Diet Revolution, has sold even more. The current plan has four steps: a 2-week “induction” period, during which the goal is to reduce carbohydrate intake to under 20 grams per day, and three periods during which carbohydrate intake is progressively raised but kept below what Atkins called “your critical carbohydrate level” for losing or maintaining weight . The dieter is permitted to eat unlimited amounts of noncarbohydrate foods “when hungry,” but, as noted above, the diet tends to suppress appetite. The plan calls for checking one’s urine for ketone bodies to ensure that the desired level of ketosis is reached. Atkins also recommended large amounts of nutritional supplements. Some physicians prolong the “induction” phase under monitoring.
Stephen Barrett, M.D.
Casazza is embarking on a new study of girls ages 7-11, recruiting 100 African-American and Caucasian girls. It will examine further the role of carbohydrates in metabolic development, along with its role in weight-loss and in the development of bone mass.
This study was funded by the National Institutes of Health, the Thrasher Research Fund and the UAB Center for Women’s Reproductive Health.
The Atkins Diets - Rules of Induction
You may eat pure protein (meat, fish and shellfish, poultry, eggs) and pure fats (butter, olive oil, mayonnaise).
Eat no more than 20 grams of carbohydrates a day in the form of salad and other vegetables, such as asparagus, broccoli and kale.
Eat absolutely no fruit, bread, grains, starchy vegetables or dairy products other than cheese, cream or butter.
Eat out as often as you wish. Just be alert to hidden carbs in gravies, sauces and dressings.
Eat no food not specifically allowed.
Aspartame may stimulate insulin production; avoid it and foods containing it.
Check the carb content of all foods you are unsure about with a carbohydrate gram counter.
Caffeine stimulates the production of insulin, so avoid regular coffee, tea and cola drinks.
Eat the amount of food that makes you feel satisfied, but not stuffed. If you’re not hungry, eat nothing or have a small protein snack to accompany your supplements.
Known for its innovative and interdisciplinary approach to education at both the graduate and undergraduate levels, the University of Alabama at Birmingham is the state of Alabama’s largest employer and an internationally renowned research university and academic health center; its professional schools and specialty patient-care programs are consistently ranked among the nation’s top 50.
EDITOR’S NOTE: The University of Alabama at Birmingham (UAB) is a separate, independent institution from the University of Alabama, which is located in Tuscaloosa. Please use University of Alabama at Birmingham on first reference and UAB on all consecutive references.
Source: University of Alabama at Birmingham