A 48-year-old man comes to the office to discuss weight loss. For the past 6 months, he and his wife have been following a low-fat diet and exercising regularly. However, the patient has not achieved satisfactory weight loss. Medical history is unremarkable, but family history is notable for cardiovascular disease in both parents. The patient quit smoking 13 years ago and has a 10-pack-year history; he drinks alcohol only on social occasions.
Blood pressure is 133/86 mm Hg and pulse is 78/min. BMI is 29 kg/m². The patient appears moderately overweight but comfortable. Physical examination is otherwise normal.
Laboratory results show fasting blood glucose 105 mg/dL, total cholesterol 210 mg/dL, HDL cholesterol 40 mg/dL, and triglycerides 185 mg/dL.
The patient indicates that he and his wife intend to start a very low-carbohydrate diet. Compared to his current program, which of the following is this patient most likely to experience after changing his diet?

Question

Quizplus · Accepted Answer

Numerous weight loss diets have been promoted, including low-fat, low-carbohydrate, balanced low-calorie, and Mediterranean-style (high intake of monounsaturated fats, vegetables, and grains; low intake of red meat). Studies on the relative effectiveness of various weight loss diets have not shown clear superiority of one over another. Successful weight loss likely depends more on patient factors (eg, total caloric intake, long-term adherence, concurrent exercise) than on the specific dietary plan. Low-carbohydrate diets can produce rapid initial weight loss. They are more effective for weight loss in the short term than low-fat diets, although this is likely due to mobilization of glycogen stores and fluid losses rather than fat loss. Long-term studies have not found greater sustained weight loss compared with low-fat diets at 1 year (Choice A). Low-carbohydrate diets that emphasize mono- and polyunsaturated fat sources (eg, fish, poultry, legumes) have been associated in observational studies with reduced cardiovascular and all-cause mortality (Choice B). However, low-carbohydrate diets are associated with increased incidence of unpleasant gastrointestinal effects (eg, bloating, diarrhea, constipation), headache, and reduced exercise tolerance. (Choices D and E) Both low-fat and low-carbohydrate diets are associated with a reduction in fasting glucose and blood pressure, and comparative studies have not noted a clinically significant difference between the 2 strategies in these measures. Educational objective: Low-carbohydrate diets can produce rapid initial weight loss. Compared with low-fat diets, low-carbohydrate diets produce similar long-term weight loss and improvements in blood pressure and fasting blood glucose. Low-carbohydrate diets are associated with increased incidence of unpleasant gastrointestinal effects. __________ References: Relative merits of low-carbohydrate versus low-fat diet in managing obesity. (http://www.ncbi.nlm.nih.gov/pubmed/26192936) A critical review of low-carbohydrate diets in people with type 2 diabetes. (http://www.ncbi.nlm.nih.gov/pubmed/26413954) Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors: a meta-analysis of randomized controlled clinical trials. (http://www.ncbi.nlm.nih.gov/pubmed/23035144)

A 48-Year-Old Man Comes to the Office to Discuss Weight