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2017.04.24

What does the science say regarding dietary supplementation and nutrition for weight loss and maintenance of proper body composition?

During the past thirty years, the United States has succumbed to a pervasive obesity epidemic (Flegal et al., 2002; Lewis & Schneiderman, 2006; Mokdad et al., 2001; Ogden et al.., 2006). In 1980, fewer than 47% of Americans were overweight (body mass index [BMI] >25 kg/m2) and less than 15% were obese (BMI > 30 kg/m2).  Today, approximately 70% of Americans are overweight, and over 35% of men and 40% of women are obese (Flegal et al., 2016).  Annual deaths from obesity in the United States are more than 120,000, overweight/obesity is second only to tobacco use as a public health threat and as the leading cause of preventable death in the United States, and more people are now overweight/obese than people who smoke, live in poverty, or drink heavily (Flegal et al., 2002; Flegal et al., 2005; Ogden et al., 2012).

Obese individuals and even individuals with mild to moderate overweight have increased risks for chronic conditions, many of which are associated with a relatively high rate of morbidity and mortality, such as type 2 diabetes, hypertension, and coronary heart disease (Burton & Foster, 1985; Ditschuneit & Flechtner-Mors, 2001; Pasman et al., 1999a; Pi-Sunyer et al., 1998; Westerterp-Plantenga, Kempen, & Saris, 1998; World Health Organization, 2000). The risks associated with many of these co-morbid conditions may be reduced with modest weight loss.  Clinical studies suggest that minimal, sustained weight loss of 5% to 10% can reduce or eliminate obesity-related disorders (Ditschuneit & Flechtner-Mors, 2001).  Weight control methods often produce short-term success, but sustained weight maintenance is difficult to reach (Pasman, Saris, & Westerterp-Plantenga, 1999b; Westerterp-Plantenga, Kempen, & Saris, 1998).  Weight cycling and relapse of body weight are common features after a weight loss intervention.  The maintenance of treatment-induced weight loss thus remains a significant challenge in the management of obesity (Leermakers et al., 1999).

Conventional Western medicine has had minimal application in treating overweight and obesity by only offering limited options, such as gastric bypass surgery. In addition, conventional medicine is unlikely to safely meet the expectation of treating overweight and obesity through appetite suppression or other pharmacological agents.  Therefore, many consumers have turned to nutraceuticals to treat not only weight problems, but a host of other illnesses and disorders, with total sales of dietary supplements at $35 billion in 2012 (Nutrition Business Journal, 2012).  Many dietary supplements are being marketed for weight loss today and their formulations vary from single nutrients to combinations of many different vitamins and nutrient and non-nutrient elements (Dwyer, Allison, & Coates, 2005).  In addition, many botanical and other dietary supplements for weight loss have active ingredients that are unknown or uncharacterized.  For example, caffeine, carnitine, green tea, conjugated linoleic acid, and chromium are just a few nutrients that have been proclaimed to have an effect on fat metabolism, but only caffeine and green tea have any data to support their potential for fat metabolism-enhancement (Jeukendrup & Randell, 2011).  While several studies have observed positive effects of green tea extract on fat metabolism and hence weight loss, the overall findings are uncertain, perhaps due to study design inconsistencies, but also because the mechanistic actions of green tea extract on fat metabolism are vague and hardly supported (Hodgson et al., 2013).  Other touted weight loss supplements have even less scientific evidence, and although may have some promise, the marketing will likely continue to surpass the scientific justification.

Additionally, despite high rates of supplement usage among the overweight and obese and the limited findings of the efficacy of individual therapies on the amelioration of effective weight loss (Dwyer, Allison, & Coates, 2005), few clinical trials have tested a regimen of supplements in a synergistic paradigm as a way to reduce body weight. Nutrient-containing dietary supplements are helpful for achieving nutrient adequacy on hypocaloric diets, but evidence-based clinical trials on dietary supplementation to achieve weight loss are unknown and needed.  Thus, the area of dietary supplements and weight loss is widely understudied and lacks any conclusive answer for overweight/obese consumers.

Perhaps the most effective dietary strategy for sustaining weight loss and achieving a healthy body composition for obese individuals involves the use of a very-low-caloric diet (VLCD). A VLCD allows no more than 800 calories per day with a high amount of protein and minimal carbohydrate to encourage weight loss, minimize loss of lean tissue, and supplement with micronutrients, electrolytes, and essential fatty acids to guarantee sufficient nutritional status (Dhindsa, 2003).  However, these diets are not recommended for routine weight management, as standard guidelines suggest that this diet style should only be conducted with the supervision of a treating physician (Jensen et al., 2014).  While prior reviews on the effect of VLCD for weight loss found that they are successful in the short-term (Asher, 2013; Tsai & Wadden, 2006), their sustainability for 12 months or more is unknown (Asher, 2013; Mulholland et al., 2012; Tsai & Wadden, 2006).  Nonetheless, a very recent review suggests that with VLCD along with behavior modification attain greater long-term weight loss than behavior modification alone, are bearable, and cause little adverse effects, demonstrating they are likely underutilized compared to standard recommendations (Parretti et al., 2016).

In summary, obesity is a significant and increasing problem that is not currently being abated successfully by conventional medical modalities. As consumers turn toward dietary supplements to help with weight loss, the data are not conclusive for any particular nutrient or formula to help improve body composition, save for some minor support for green tea extract.  Nonetheless, the VLCD can be an effective way to achieve long-term weight loss, provided it is combined with the proper behavior modification in the form of emotional and psychological support.  Once a healthy weight is achieved, then consideration could be given to taking a more balanced approach to a healthy diet, key dietary supplementation, and a consistent and intense exercise training regimen.  A healthy weight can be achieved, but it requires discipline and consistency while eliminating old habits and poor patterns over time.

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