A recent study in Obesity in May 2016 (1) reported very discouraging findings for a group of participants who had lost weight on “The Biggest Loser” (TBL) reality TV show: not only did almost all of them regain a significant amount of weight over the 6-year period afterwards, but they also had lower resting metabolic rates than expected for their body weights, even six years later. With media spin, it won't be a surprise if everyone just gives up staying thinner and blames excess weight on a faulty, and unchangeable, metabolism.
However, there are a number of factors that impact body weight and weight regain after loss, not just resting metabolism. How much physical activity people do daily and what type, the types of food that people eat, how many calories they actually ingest daily and when they consume them, stress management, and sleep patterns also have an impact on weight maintenance and regain after loss, among other things.
My issues with this study and with TBL’s approach to weight loss are the following:
(1) The way the contestants go about losing large amounts of body weight in a relatively short time is not sustainable as a lifestyle to maintain body weight after loss;
(2) Although TBL participants exercise (a whole lot) during their initial, six-month weight loss period—which helps prevent even greater losses of lean body mass than they would experience otherwise with such extreme weight loss—it does not prevent all muscle mass loss, which means that their total amount of muscle decreased (regardless of their relative ratios of fat and non-fat tissues);
(3) Dietary changes are as important to weight management as they are to weight loss, and diet is de-emphasized on TBL, with a focus instead on reality-TV- and entertainment-driven crazy amounts and types of physical activity; and
(4) TBL approach is not the same as that reported by successful losers and maintainers followed in the National Weight Control Registry (http://www.nwcr.ws).
With regard to that last point, much can be learned from studying members of the National Weight Control Registry (NWCR), which only includes people with medically documented weight losses of at least 30 pounds that were maintained for at least a year. While the members lost and keep the weight off in a variety of ways, most report continuing to maintain a low-calorie, low-fat diet and doing high levels of physical activity. Among the NWCR members: 78% eat breakfast every day; 75% weigh themselves at least once a week; 62% watch less than 10 hours of TV per week; and 90% exercise, on average, about 1 hour per day.
In one study, NWCR subjects spent significantly more time per day in sustained bouts of moderate-to-vigorous physical activity than their overweight counterparts (41.5 ± 35.1 min/day vs. 19.2 ± 18.6 min/day) and marginally more than normal weight adults (25.8 ± 23.4), so they were actually getting more daily exercise than most (2). A 10-year study of self-reported weight loss and behavior change in 2,886 NWCR participants (78% female; mean age 48 years), and more than 87% were still maintaining at least a 10% weight loss after five and ten years (3). Even though decreases in leisure-time physical activity, dietary restraint, and frequency of self-weighing, along with increases in percentage of energy intake from fat and disinhibition, were associated with greater weight regain, the majority of weight lost by NWCR members has been maintained over 10 years.
Others have reported that the differences in total weight gain in people being overfed similar amounts of calories was likely due to the total amount of daily movement that they engaged in, including standing, fidgeting, and taking more steps, not just planned exercise (4). Weight maintenance may, therefore, as influenced by total daily activity that is not necessarily reported or measured like most moderate and vigorous exercise is.
Weight maintenance may also be as simple as staying on top of body weight. NWCR studies have shown that consistent self-weighing may help individuals maintain their successful weight loss by allowing them to catch weight gains before they escalate and make behavior changes to prevent additional weight gain, and decreased self-weighing frequency is independently associated with greater weight regain (5).
Clearly, the body is a complex system with many different bodily and environmental factors adding to the mix. In the TBL study, there was no indication that they controlled for the potential effects of the last bout of exercise on resting metabolic measures (at least this was not reported on in the study), although exercise can impact metabolism for 2-72 hours afterwards They did not measure or report on the types of foods that the “biggest losers” were eating, although fiber is known to improve the gut microbiota and may be related to successful weight loss and maintenance (7). While many reported being active, doing cardio training versus resistance can have differing impacts on muscle glycogen storage, muscle mass, and insulin action, as well as resting metabolism, and the type of activity done was not reported in TBL study.
So, before we jump to any conclusions and blame all weight regain on something completely outside our control (a lower resting metabolism) and relinquish all personal responsibility for weight maintenance, make sure to consider all of the other potentially confounding variables that have not necessarily been well studied at this point. Let’s not just rely on and sensationalize the results of one small pilot study of “biggest losers,’ but rather take away lessons learned from the successful maintainers who are members of the much more reality-based NWCR.
References cited:
1. Fothergill E, Guo J, Howard L, Kerns JC, Knuth ND, Brychta R, Chen KY, Skarulis MC, Walter M, Walter PJ, Hall KD: Persistent metabolic adaptation 6 years after “the biggest loser” competition. Obesity 2016:n/a-n/a
2. Catenacci VA, Grunwald GK, Ingebrigtsen JP, Jakicic JM, McDermott MD, Phelan S, Wing RR, Hill JO, Wyatt HR: Physical activity patterns using accelerometry in the national weight control registry. Obesity (Silver Spring) 2011;19:1163-1170
3. Thomas JG, Bond DS, Phelan S, Hill JO, Wing RR: Weight-loss maintenance for 10 years in the national weight control registry. Am J Prev Med 2014;46:17-23
4. Levine JA, Eberhardt NL, Jensen MD: Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science 1999;283:212-214
5. Butryn ML, Phelan S, Hill JO, Wing RR: Consistent self-monitoring of weight: A key component of successful weight loss maintenance. Obesity (Silver Spring) 2007;15:3091-3096
6. Wang X, Patterson BW, Smith GI, Kampelman J, Reeds DN, Sullivan SA, Mittendorfer B: A ~60-min brisk walk increases insulin-stimulated glucose disposal but has no effect on hepatic and adipose tissue insulin sensitivity in older women. J Appl Physiol (1985) 2013;114:1563-1568
7. Blaut M: Gut microbiota and energy balance: Role in obesity. Proc Nutr Soc 2014:1-8