Benefits of lifestyle modification in NAFLD

Excessive foodstuffs, particularly in the form of complex carbohydrates, increased fructose consumption and saturated fats, combined with a sedentary lifestyle have contributed to the epidemic of obesity, dysregulated metabolism and NAFLD. Our knowledge of the pathological consequences of poor dietary choices and lack of adequate exercise on adipose tissue, skeletal muscle and the liver is improving, and this will help in establishing more specific guidelines for the proper nutrient intake and exercise regimens that will improve underlying metabolic pathways and ultimately decrease the incidence and severity of NAFLD. For now it seems that diets aimed at reducing total daily energy intake, based on either a low processed carbohydrate, or low-fat macronutrient platform, aimed at achieving about a 10% weight reduction, will improve both metabolic and histopathological abnormalities in a diverse group of NAFLD patients. Moderate exercise, preferably a combination of aerobic and restrictive, performed 3-4 times per week, expending about 400 calories each time seems adequate to augment improvement in the metabolic profiles of patients with NAFLD. More rigorous, controlled studies, of longer duration and defined histopathological end-points comparing diet alone, exercise alone and diet plus exercise are needed before better, evidence-based lifestyle modification guidelines can be established, since several questions remain unanswered. Does lifestyle modification work equally well in men versus women? Do younger patients respond better than older patients to lifestyle modification? Is there a diversity of response among various ethnic groups or in patients with fatty liver alone compared with patients with more progressive disease? Do diabetic patients with NAFLD have a better histopathological response to lifestyle modification than insulin-resistant patients without diabetes and, if so, does the same amount of weight loss equate to histopathological improvement, or do these patients need to lose more or less weight, or simply need to exercise more? Finally, are there different lifestyle modification approaches, i.e. diet alone versus diet and aerobic exercise, that work better for different patient populations?