In October 2003, the North American Association for the Study of Obesity held its conference in Fort Lauderdale, Florida. Here we provide summaries of some of the more interesting research presented at the conference.
A Salad Before Meals Helps You Eat Less
Eating a large low-calorie salad as a first course may help lower the amount of calories you eat in the entire meal.
Barbara Rolls, MD, and a research team from Pennsylvania State University enrolled 33 women in a study, inviting them to the lab for lunch once a week for seven weeks. On six of the test days, the women were served a first-course salad, which they were required to finish. On the seventh test day, the women were allowed to skip to the entrée.
Researchers found that when individuals ate three cups of low-calorie salad before lunch, they ate less during the entire meal-consuming 12 percent fewer calories-than when they did not eat a first-course salad. When they had one and a half cups of low-calorie salad, the women consumed 7 percent fewer calories overall than when they ate no salad.
Soy May Reduce Your Risk of Heart Problems
Liquid soy meal replacements may be useful in managing weight for overweight people with type 2 diabetes, according to Los Angeles researchers.
Results of a six-month randomized study show that type 2s can lose weight and reduce their cardiovascular risk factors, including cholesterol and triglycerides, using soy meal replacements.
The study included 50 people with type 2 who also had high levels of C-reactive protein-a leading marker for inflammation and risk of cardiovascular disease.
Each group was randomly assigned to either meal replacement with soy (Slim-Fast soy meal replacement) or to an individualized exchange diet plan for six months. Participants in the soy meal replacement group replaced two meals per day during the initial weight-loss period and then one per day for weight maintenance. With the individualized meal plan, subjects met with a registered dietitian who instructed them on ways to reduce caloric intake.
People in the soy meal replacement group experienced a 25 percent reduction in C-reactive protein as well as significant decreases in total cholesterol (23.3 percent) and triglycerides (19.8 percent).
A Promising New Approach for Weight Loss.
Researchers at Tufts-New England Medical Center say that a new surgical procedure, called the implantable gastric stimulator, may offer a way to lose weight without the types of surgical complications associated with procedures involving gastrointestinal alterations.
The implantable gastric stimulation system uses an implanted electronic pulse generator to deliver electrical stimulation to the stomach. This, in turn, reduces feelings of hunger, without altering gastrointestinal anatomy.
In a study, 30 individuals had two bipolar leads implanted in the muscular wall of the stomach. The leads were connected to an electrical generator (not unlike a pacemaker) and were placed under the abdominal skin. After a follow-up period of eight to nine months, 80 percent of the patients had lost weight, with 60 percent losing more than 10 percent of their excess weight. None of the patients reported complications.
Calorie-Dense Foods Are Detrimental to Weight Loss
Large portions apparently lead people to eat more, but big portions of calorie-dense food result in even higher calorie consumption without providing additional satisfaction, according to a new Penn State study.
“Large portions of calorie-dense foods put people at risk for overconsuming calories,” says Tanja Kral, doctoral candidate in nutritional sciences, who conducted the study. “By reducing the calorie density of foods, people can afford to eat satisfying portions of food while at the same time feeling full on fewer calories.”
Kral and associates selected 39 normal-weight and overweight women to eat breakfast, lunch and dinner once a week for six weeks in Penn State’s Laboratory for the Study of Human Ingestive Behavior. The breakfasts and dinners were standardized, but the main entrée at lunch was formulated to vary in caloric density as well as portion size.
The investigators observed that energy density and portion size had a cumulative impact on how many calories the women consumed. In fact, the women consumed 56 percent more calories when they were given the largest, high-energy-density entrée, compared to meals in which smaller, lower-energy-density foods were served. It appears that a combination of large portion size with foods higher in energy density leads to overeating.
Diet Wars: Low-Fat Vs. Low-Carb
Low-carbohydrate diets might help you lose weight, even without controlling calorie intake, according to Harvard researchers.
The study compared people who were on low-fat diets with those on low-carbohydrate diets, closely measuring and monitoring the calories consumed by both groups.
For this preliminary study, Penelope Greene, MD, and the research team enrolled 21 subjects, dividing them into three groups. One group consumed under strich caloric monitoring, a diet low in fat but high in carbohydrates and protein (1500 kcal for women, 1800 kcal for men), while the third group ate low-carbohydrate foods but more calories (1800 kcal for women, 2100 kcal for men).
After 12 weeks, all three diet groups lost a significant amount of weight, although the low-carbohydrate dieters with lower caloric intake lost the most.