4.1.1 Weight Loss Goals and Energy Restriction
Weight Losing through diet and exercise is the primary strategy. It is essential to consider realistic goals to promote a sustained and healthy weight loss. Considering that most NAFLD/NASH patients are overweight or obese, a weight loss strategy ranging from 5% to 10% of the initial weight in 6 months is desirable.43 According to different therapeutic guidelines for NAFLD/NASH (Table 1.1), a weight reduction of 3%–10% is expected. Improvements in simple steatosis are observed with a 3%–5% of body weight loss, whereas a 7%–10% is associated with improvements in the histopathological features of NASH.40 However, a weight loss ≥10% is needed for resolution of NASH and fibrosis regression.44 Energy restriction through diet is required to achieve weight loss. Therefore, it is recommended that energy be reduced from 500 kcal/day to 1000 kcal/day or 30% less of the total energy requirement. The energy intake recommended for women is 1200–1500 kcal/day and 1500–1800 kcal/day for men (considering physical activity and personal requirements). This aim intends to promote a healthy weight loss which comprises around 0.5–1 kg per week.43 In contrast, a dramatic weight loss of >1.6 kg/week should be avoided as this may worsen NASH and promote the development of gallstones.45
Weight Management: Finding the Healthy Balance
Jacqueline B. Marcus MS, RD, LD, CNS, FADA, in Culinary Nutrition, 2013
Losing weight and keeping it off is difficult because it takes a conscious daily effort to monitor calories and activities. The temptation to use dietary aids is alluring. Turning to pills and potions to take the weight off fast is a lot easier than dieting and exercising, no matter what the cost. But are they safe, and what are the long-term effects?
Herbal and dietary supplements are common weight loss aids. In the United States, the Dietary Supplement and Health Education Act of 1994 (DSHEA) allows manufacturers to classify herbal products and nutritional supplements as foods. But it also allows manufacturers to bypass some strict regulations of the FDA. As a result, weight-loss aids are not subject to the same rigorous standards as prescription drugs or over-the-counter medications. Some can be marketed with limited proof of effectiveness or safety. Manufacturers may make health claims based on their own review and interpretation of studies without FDA authorization. However, the FDA can take a product off the market if it is proven to be dangerous. This is especially important with the number of products that are now available through the Internet. The US Federal Trade Commission (FTC) helps to monitor trafficking. Some of these diet aids are shown in Table 10-2 [24–27]. Because there is no assurance that these products are safe or effective, like other alternative approaches to diet and health, let the buyer beware. Some potential long-term effects can be quite dangerous.
A number of prescription and over-the-counter drugs are available to combat the growing health problem of obesity. They act by inhibiting the enzyme lipase that is needed for fat digestion; numbing the taste buds; raising the brain chemical norepinephrine, which signals satiety; suppressing appetite; and other means.
Potential side effects include decreased absorption of fat-soluble vitamins, gastrointestinal disorders, and increased blood pressure and heart rate. Even “Dieter’s Tea,” readily available at some supermarkets, may cause severe extreme dehydration, gastrointestinal problems, and sometimes even death.
As body weight decreases, there is a proportional reduction in the weight and strength of the diaphragm and the function of respiratory muscles. In emphysema, the hyperinflated lungs alter the fiber length of the respiratory muscles and impair their efficiency. With malnutrition, the diaphragm, intercostal, and accessory muscles are catabolized for energy, resulting in a decrease in inspiratory capacity. Infection, inflammation, and decreased protein intake lead to a drop in serum albumin, which lowers the oncotic pressure and results in pulmonary edema. Undernutrition also affects the pulmonary parenchyma by diminishing collagen synthesis and increasing proteolysis. This may manifest as decreased surfactant production and alveolar collapse.