Obesity medical therapy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Karol Gema Hernandez, M.D. [2]

Overview[edit | edit source]

The main treatment for obesity is to reduce body fat by eating fewer calories and exercising more. A beneficial side effect of exercise is to increase muscle, tendon, and ligament strength, which helps to prevent injury from accidents and vigorous activity. Diet and exercise programs produce an average weight loss of approximately 8% of total body mass (excluding program drop-outs). Not all dieters are satisfied with these results, but a loss of as little as 5% of body mass can create large health benefits.

Much more difficult than reducing body fat is keeping it off. Eighty to ninety-five percent of those who lose 10% or more of their body mass by dieting regain all that weight back within two to five years. The body has systems that maintain its homeostasis at certain set points, including body weight. Therefore, keeping weight off generally requires making exercise and eating right a permanent part of a person's lifestyle. Certain nutrients, such as phenylalanine, are natural appetite suppressants which allow resetting of the body's set point for body weight.

Clinical Practice Guidelines[edit | edit source]

Clinical practice guidelines are available^[1][2][3][4]; however, some of the guidelines do not follow recommendations for trustworthiness by the Institute of Medicine^[3][4].

2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society (DO NOT EDIT) ^[1][edit | edit source]

Matching Treatment Benefits With Risk Profiles (Reduction in Body Weight Effect on CVD Risk Factors, Events, Morbidity and Mortality) (DO NOT EDIT)[edit | edit source]

Diets for Weight Loss (Dietary Strategies for Weight Loss) (DO NOT EDIT)[edit | edit source]

ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death - Obesity, Dieting, and Anorexia (DO NOT EDIT) ^[5][edit | edit source]

ACP 2005 Guidelines for Pharmacologic and surgical management of obesity in primary care^[6][edit | edit source]

In a clinical practice guideline by the American College of Physicians, the following five recommendations are made:^[2]

1. People with a BMI of over 30 should be counseled on diet, exercise and other relevant behavioral interventions, and set a realistic goal for weight loss.
2. If these goals are not achieved, pharmacotherapy can be offered. The patient needs to be informed of the possibility of side-effects and the unavailability of long-term safety and efficacy data.
3. Drug therapy may consist of sibutramine, orlistat, phentermine, diethylpropion, fluoxetine, and bupropion. For more severe cases of obesity, stronger drugs such as amphetamine and methamphetamine may be used on a selective basis. Evidence is not sufficient to recommend sertraline, topiramate, or zonisamide.
4. In patients with BMI > 40 who fail to achieve their weight loss goals (with or without medication) and who develop obesity-related complications, referral for bariatric surgery may be indicated. The patient needs to be aware of the potential complications.
5. Those requiring bariatric surgery should be referred to high-volume referral centers, as the evidence suggests that surgeons who frequently perform these procedures have fewer complications.

A clinical practice guideline by the US Preventive Services Task Force (USPSTF) concluded that the evidence is insufficient to recommend for or against routine behavioral counseling to promote a healthy diet in unselected patients in primary care settings, but that intensive behavioral dietary counseling is recommended in those with hyperlipidemia and other known risk factors for cardiovascular and diet-related chronic disease. Intensive counseling can be delivered by primary care clinicians or by referral to other specialists, such as nutritionists or dietitians.^[7][8]

Exercise[edit | edit source]

Exercise requires energy (calories). Calories are stored in body fat. The body breaks down its fat stores in order to provide energy during prolonged aerobic exercise. The largest muscles in the body are the leg muscles, and naturally these burn the most calories, which make walking, running, and cycling among the most effective forms of exercise for reducing body fat.

A meta-analysis of randomized controlled trials by the international Cochrane Collaboration found that "exercise combined with diet resulted in a greater weight reduction than diet alone".^[9]

Dieting[edit | edit source]

In general, dieting means eating less. Various dietary approaches have been proposed, some of which have been compared by randomized controlled trials:

• A comparison of Dr. Atkins', Slim-Fast's, Weight Watchers', and Rosemary Conley's diets found no significant differences.^[10]
• A comparison of Atkins diet, Zone diet, Weight Watchers, and Ornish diet noted:^[11]

"all 4 diets resulted in modest statistically significant weight loss at 1 year, with no statistically significant differences between diets"

"The higher discontinuation rates for the Atkins and Ornish diet groups suggest many individuals found these diets to be too extreme"

Low Carbohydrate versus Low Fat[edit | edit source]

Many studies have focused on diets that reduce calories via a low-carbohydrate (Atkins diet, Zone diet) diet versus a low-fat diet (LEARN diet, Ornish diet). The Nurses' Health Study, an observational cohort study, found that low carbohydrate diets based on vegetable sources of fat and protein are associated with less coronary heart disease.^[12]

A meta-analysis of randomized controlled trials by the international Cochrane Collaboration in 2002 concluded^[13] that fat-restricted diets are no better than calorie restricted diets in achieving long term weight loss in overweight or obese people.

A more recent meta-analysis that included randomized controlled trials published after the Cochrane review^[14][15][11] found that "low-carbohydrate, non-energy-restricted diets appear to be at least as effective as low-fat, energy-restricted diets in inducing weight loss for up to 1 year. However, potential favorable changes in triglyceride and high-density lipoprotein cholesterol values should be weighed against potential unfavorable changes in low-density lipoprotein cholesterol values when low-carbohydrate diets to induce weight loss are considered."^[16]

The Women's Health Initiative Randomized Controlled Dietary Modification Trial^[17] found that a diet of total fat to 20% of energy and increasing consumption of vegetables and fruit to at least 5 servings daily and grains to at least 6 servings daily resulted in:

• No reduction in cardiovascular disease^[18]
• An insignificant reduction in invasive breast cancer^[19]
• No reductions in colorectal cancer^[20]

Additional recent randomized controlled trials have found that:

• A comparison of Atkins, Zone diet, Ornish diet, and LEARN diet in premenopausal women found the greatest benefit from the Atkins diet.^[21]

• The choice of diet for a specific person may be influenced by measuring the invididual's insulin secretion:

In young adults "Reducing glycemic [carbohydrate] load may be especially important to achieve weight loss among individuals with high insulin secretion."^[22] This is consistent with prior studies of diabetic patients in which low carbohydrate diets were more beneficial.^[23][24]

Low Glycemic Index[edit | edit source]

"The glycaemic index factor is a ranking of foods based on their overall effect on blood sugar levels. Low glycaemic index foods, such as lentils, provide a slower more consistent source of glucose to the bloodstream, thereby stimulating less insulin release than high glycaemic index foods, such as white bread."^[25][26]

The glycemic load is "the mathematical product of the glycemic index and the carbohydrate amount".^[27]

In a randomized controlled trial that compared four diets that varied in carbohydrate amount and glycemic index found complicated results^[28]:

• Diet 1 and 2 were high carbohydrate (55% of total energy intake)
  • Diet 1 was high-glycemic index
  • Diet 2 was low-glycemic index
• Diet 3 and 4 were high protein (25% of total energy intake)
  • Diet 3 was high-glycemic index
  • Diet 4 was low-glycemic index

Diets 2 and 3 lost the most weight and fat mass; however, low density lipoprotein fell in Diet 2 and rose in Diet 3. Thus the authors concluded that the high-carbohydrate, low-glycemic index diet was the most favorable.

A meta-analysis by the Cochrane Collaboration concluded that low glycemic index or low glycemic load diets led to more weight loss and better lipid profiles. However, the Cochrane Collaboration grouped low glycemic index and low glycemic load diets together and did not try to separate the effects of the load versus the index.^[25]

Drugs[edit | edit source]

References[edit | edit source]

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