Obesity is an abnormal accumulation of body fat, usually 20 percent or more over an individual’s ideal body weight.
Ideal body weight may be found by using body mass index (BMI). Body Mass Index (BMI) is equal to weight (kg) divided by height squared (meters), or weight (pounds) x 703 divided by height squared (inches).
Prevalence of Obesity
Childhood and adolescent obesity has increased from 5% to 16% during the last 20 years. Adulthood obesity has increased from 12% to 21% in 10 years. 16 million US adults with BMI over 35 are present and 60 million US obese adults (BMI > 30) have been found.
Factors predispose to obesity
Genetic – familial tendency
Sex – women more susceptible
Activity – lack of physical activity
Psychogenic – emotional deprivation, depression
Social class – poorer classes
Alcohol – problem drinking
Smoking – cessation smoking
Prescribed drugs – tricyclic derivatives
Several medicines have been found to cause weight gain. These include insulins and sulfonylureas for diabetes, tricyclics for depression, valproic acid for seizures, clonidine for hypertension and progesterones among others.
Weight Gain: How Does It Happen?
Weight gain simply occurs due to energy imbalance (calories consumed not equal to calories used) over a long period of time due to a combination of several factors, including:
Leptin is a protein hormone secreted by adipocytes. Its levels correlate with lipid content of cells. Leptin acts on the hypothalamus to reduce hunger and to stimulate energy expenditure
Ghrelin is a hormone secreted in the stomach and acts on the hypothalamus to stimulate appetite. Levels peak just before meals and drop afterwards.
Dieting decreases leptin levels, reducing metabolism and stimulating appetite. Ghrelin levels in dieters are higher after weight loss. The body steps up ghrelin production in response to weight loss. The higher the weight loss, the higher the ghrelin levels
Health Consequences of Obesity
Obesity is the major cause of preventable death. It increases mortality from all causes. It increases risk of
Endometrium, breast, prostate, colon cancers
Diabetes type 2
Coronary artery disease
Sleep apnea & respiratory problems
Assessing the patient’s readiness and willingness to lose weight is very important. Unfortunately those who are most concerned about their weights are not necessarily those who are at the highest health risk. Those who are unable or unwilling to embark on a weight reduction program, but are willing to take steps to avoid further weight gain or perhaps to work on other risk factors such as cigarette smoking, should be encouraged to do so.
For those not ready to act, the issue should be deferred and brought up at the next visit.
Assessment includes assessing if the patient is overweight or obese and what are the key health issues.
- Measure BMI
- Measure waist circumference -“Apple shaped” body is higher risk for diabetes, cardiovascular diseases, hypertension. Waist larger than 40 inches for men and
35 inches for women is significant.
Assess for other risk factors
- existing high risk diseases like coronary heart disease; other atherosclerotic diseases; type 2 diabetes; sleep apnea
- Diseases associated with obesity ike gynecological problems; osteoarthritis; gallstones; stress incontinence
- Cardiovascular risk factors (3 or more = high risk) -Cigarette smoking; Hypertension; LDL >130; HDL <35; fasting glucose = 110 to 125; family history of premature CHD; men age > 45; women age > 55
- Other risk factors including physical inactivity; elevated serum triglycerides
- Medications associated with obesity
A multi-faceted approach is always the best targeting:
Initial goal should be 10% weight loss which significantly decreases risk factors. Rate of weight loss should be around 1 to 2 pounds per week. Reduction of caloric intake to around 500-1000 per day. Slow weight loss is more stable while rapid weight loss is almost always followed by weight gain. Rapid weight loss increases risk for gallstones & electrolyte abnormalities.
One should aim for 4 – 6 months of weight loss effort. Most people will lose 20 to 25 pounds. After 6 months, weight loss is more difficult because Ghrelin & Leptin are at work!
One must set goals for weight maintenance for next 6 months, then reassess.
Weight reduction with dietary treatment is in order for virtually all patients with a BMI 25-30 who have comorbidities and for all patients over BMI 30.
Strategies of dietary therapy include teaching about calorie content of different foods, food composition (fats, carbohydrates, and proteins), reading nutrition labels, types of foods to buy, and how to prepare foods.
Low-Calorie Step I Diet
1000 to 1200 kcal/day for women
1200 to 1600 kcal/day for men
Adjust for current weight & activity
Too hungry? increase kcal by 100 – 200/day
Not losing? decrease kcal by 100 – 200/day
Physical activity should be an integral part of weight loss. Physical activity alone is less successful than a combined diet & exercise program. Increased activity alone does not decrease weight but sustained activity does prevent weight regain. It reduces risk for heart disease and diabetes.
One should start physical activity slowly and avoid injury, then increase intensity and duration gradually. Long-term goal should be 30 to 45 minutes or more of physical activity
5 or more days per week, burn 1000+ calories per week
Keep a journal of diet and activity. This is a very powerful intervention! Set specific goals for:
Track improvement by weighing and measurements on a regular basis.
Focus on the goals.
Plan meals and activity
Develop reminder systems
Anticipate temptations & plan resistance
Limit quantities, but do not deprive yourself
Have confidence in your ability to succeed
Do positive self-talk
Pharmacotherapy for Weight Loss
Pharmacotherapy is adjunct to diet and physical activity and applied when BMI ≥ 30 or BMI ≥ 27 with other risk factors. It should not be used for cosmetic weight loss. It is used only when 6-month trial of diet & physical activity fails to achieve weight loss.
The drugs are only modestly effective causing 2 to 10 kilogram loss, most occurs in the first 6 months. If patient does not lose 2 kilograms in the first 4 weeks, success is unlikely. If the first 6 months is successful, continue medication as long as it is effective in maintaining weight, and adverse effects are not serious.
Sibutramine (Merida) or Orlistat (Xenical) may be used.
Weight Loss Surgery
Types of Obesity Surgery:
1. Restrictive Surgery – uses bands or staples to create food intake restriction:
Vertical Banded Gastroplasty (VBG) – is a “pure” restrictive surgery since it only involves surgically creating a stomach pouch. VBG uses bands and staples and is the most frequently performed procedure for obesity surgery.
Gastric Banding – involves the use of a band to create the stomach pouch.
Laparoscopic Gastric Banding (Lap-Band), approved by the FDA in June 2001, is a less invasive procedure in which smaller incisions are made to apply the band. The band is inflatable and can be adjusted over time.
2. Combined Restrictive and Malabsorptive Surgery – is a combination of restrictive surgery (stomach pouch) with bypass (malabsorptive surgery), in which the stomach is connected to the jejunum or ileum of the small intestine, bypassing the duodenum.
Roux-en-Y Gastric Bypass (RGB) – is the most commonly performed gastric bypass procedure, and the second most frequently performed surgery for obesity after VBG. RGB involves a stomach pouch for food intake restriction. A direct connection, which is Y-shaped, is made from the ileum or jejunum to the stomach pouch for malabsorption.
Biliopancreatic Diversion (BPD) – is one of the most complicated obesity surgery, sometimes involving the removal of a portion of the stomach. The remaining section of the stomach is connected to the ileum. BPD successfully promotes weight loss, but this procedure is typically used for persons with severe obesity who have a BMI of 50 or more
100 pounds overweight or more
Or, BMI > 40
Or, BMI > 35 and 2 significant comorbidities
Age 18 to 60
Documented failure at nonsurgical efforts
Complications of surgery
Mortality is less than 1% in healthy young adults with BMI < 50 while it is 2-4% in patients with disease and BMI > 60. Operative complications occur in < 10% of patients. Late complications are uncommon and include:
Vitamin B12 & iron deficiency
Weight loss failure
Neurologic symptoms in unusual cases
Schedule a return visit in 2 to 4 weeks after starting weight loss plan
Monitor treatment effectiveness & side effects
Schedule monthly visits for first 3 months iff making favorable progress. See more frequently if monitoring medical complications or chronic disease
Reduce frequency of visits after 6 months
Monitor weight, BP, pulse at each visit
Monitor waist size intermittently
Share progress with patient; praise efforts
Share lab results with patient. Emphasize findings associated with weight reductio
Focus on medical benefits. Most weight loss doesn’t reach individual’s ‘ideal’ (cosmetic) goal