Weight Gain and Weight Loss

36 Weight Gain and Weight Loss



Weight Gain


The most common cause of weight gain is increased caloric intake, regardless of what the patient states. Though percentage of body fat as measured with calipers is more accurate than body mass index (body mass index [BMI] = weight in kilograms divided by the square of height in meters [kg/m2]) for defining obesity, BMI is clinically more practical and correlates fairly well with percentage of body fat. In adults, a normal BMI is 18.5 to 24.9 kg/m2. A value less than 18.5 kg/m2 is considered underweight. A BMI of 25.0 to 29.0 kg/m2 is considered overweight, whereas 30 kg/m2 and above is considered obese. A BMI of 40 kg/m2 or above is extremely obese. Obesity affects around one-third of all adults in the United States; two-thirds of these individuals are considered either overweight or obese. Obesity increases the risk of several chronic conditions, including hypertension, type II diabetes mellitus, hyperlipidemia, heart disease, pulmonary disease, hepatobiliary disease, several cancers, osteoarthritis, gastroesophageal reflux disease, and psychiatric illness.


Weight gain due to fluid retention occurs in patients with the nephrotic syndrome, congestive heart failure (CHF), or cirrhosis with ascites; these patients have clear signs of edema. Hypothyroidism can lead to decreased metabolic needs and weight gain, but for significant weight gain to occur, hypothyroidism must be pronounced, and it is usually clinically apparent. A low resting metabolic rate contributes to obesity in some individuals. Physiologic weight gain occurs as a result of pregnancy and premenstrual fluid retention. Drugs (e.g., steroids, nonsteroidal anti-inflammatory drugs [NSAIDs], antidepressants, lithium, anabolic steroids, and estrogens) can cause weight gain by promoting salt and water retention or by stimulating appetite.



Nature of Patient


Overweight in children is defined as age and gender-adjusted BMI higher than the 84th percentile but lower than the 95th percentile. Obesity is defined as age and gender-adjusted BMI in the 95th percentile or above. Although the most common type of obesity in children is exogenous, this diagnosis requires that the endocrine and genetic causes of obesity be considered. Children with exogenous obesity often show accelerated or at least normal linear growth and may reach puberty early. Most children with endogenous obesity are short for their age and have other associated abnormalities. All obese children with short stature should be evaluated promptly and carefully. Childhood obesity is an increasingly serious problem in the United States and has been tied to increased fast-food consumption, sweetened beverages, and sedentary lifestyle. It has been estimated that 13.9 % of children 2 to 5 years of age, 18.8% of children 6 to 11 years of age, and 17.4% of adolescents (12-19 years of age) are considered overweight. This increase in childhood obesity has led to an increase in the diagnosis of type II diabetes in children (traditionally thought of as an adult-onset disorder). Obesity in adolescents correlates directly with the amount of time spent in front of a computer or television screen. Currently, the American Academy of Pediatrics recommends limiting screen time to 2 hours per day.


Obese patients may experience depression, which can be either the result of being overweight or the cause of overeating. Some patients with mild depression due to seasonal affective disorder have a craving for carbohydrates. Their mood improves after carbohydrate ingestion.


Familial obesity probably represents an acquired propensity to overeat; various family members are short and obese. Their obesity tends to be proximal but can have a generalized distribution. Twin studies suggest that heredity plays a significant role in obesity.


Weight increase in patients with edema syndromes (e.g., cirrhosis, nephrosis, congestive heart failure) is usually accompanied by symptoms that suggest a deteriorating clinical status.



Nature of Symptoms


Patients may present complaining of weight gain, an uncontrollable appetite, an inability to diet, or garments that fit too tight. Obesity may be caused by binge eating or night-eating syndrome. The weight gain associated with fluid retention in the premenstrual period is usually described as bloating and is often accompanied by breast tenderness, breast swelling, or finger swelling. Some patients with hypothyroidism comment that their skin seems puffy or that they are unable to lose weight on diets that previously resulted in weight loss.



Associated Symptoms and Ameliorating Factors


Sudden, marked changes in weight that occur over 1 to 2 days are usually related to changes in fluid balance. These changes may range from a few pounds gained because of premenstrual edema or salt-retaining drugs to many pounds added as the result of cyclic edema. The weight gain of premenstrual edema usually dissipates after menstruation. The fluid retention that occurs with cyclic edema is relieved by the patient maintaining a recumbent posture for 48 to 72 hours. The weight gain caused by salt-retaining drugs is not continuously progressive; it levels off after a weight increase of several pounds.


When weight gain is progressive and the patient appears to be obese without evidence of edema, it is reasonably certain that the patient’s weight gain is caused by overeating. Some patients with profound obesity complain of fatigue, which may result from obstructive sleep apnea.



Precipitating and Aggravating Factors


Weight gain results from ingestion of more calories than are metabolized. Thus, although weight gain is usually related to increased caloric intake, it can also be produced by reduction of either physical activity or metabolic rate. These weight changes occur gradually.


Although most people eat less when they are tense or upset, 15% to 25% respond to stress with increased caloric intake, or reactive hyperphagia. These patients are often overweight. They eat excessively when they are depressed or anxious and likewise celebrate good times with elaborate meals.


Drug ingestion is an important factor in weight gain. Steroids, nonsteroidal anti-inflammatory drugs, anabolic steroids, estrogens, tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), and lithium may cause fluid retention and/or increased appetite, which can produce a weight gain of several pounds. Oral contraceptives increase weight by causing fluid retention, increasing appetite, and creating an anabolic effect. Psychotropic agents (e.g., tricyclic antidepressants, some phenothiazines) may produce a craving for carbohydrates in patients taking these drugs. In addition, when antidepressant drugs alleviate the anorexia of depression, a pronounced weight gain may occur. Beta blockers may cause weight gain through their induction of hypoglycemia. Smoking cessation may contribute to weight gain equivalent to approximately 200 to 300 kcal per day.

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Mar 21, 2018 | Posted by in BIOCHEMISTRY | Comments Off on Weight Gain and Weight Loss

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