Weight loss maintenance – a tortuous path

Catia Martins, førsteamanuensis fedmeforskningsgruppen, Institutt for klinisk og molekylær medisin, Medisinsk fakultet, NTNU.

The long-term maintenance of a reduced body weight remains the main challenge in obesity management, with only a small group being successful after conservative treatment (1). Physiological adaptations, such as  increased hunger and reduced energy expenditure, are activated with weight loss and are likely to be involved in relapse (2). Patients with obesity need continued support in order to overcome the above-mentioned mechanisms and succeed in the long-term.

Introduction

Obesity, defined as a body mass ­index ≥30 kg/m2, is a chronic relapsing progressive disease (3) associated with negative morbidity and mortality outcomes, which place a significant financial burden on health care systems (4). Norway is not immune to the obesity pandemic. Data from the HUNT study has shown a tremendous increase since the 1980s, with the most recent data pointing to one out of every four ­Norwegians having obesity (5). A weight loss between 5-10% of initial weight, if sustained, can have large health benefits by improving or ­preventing many of the obesity-­related risk factors and co-morbidities (6).

Weight loss

Lifestyle interventions involving diet, exercise, and behavior modification should be the cornerstone in obesity treatment. Even though exercise can induce modest weight loss, the amount required to induce clinical significant weight loss in the obese population is, in most cases, difficult to perform on a regular basis. For that reason, it is generally accepted that energy restricted diets should be the main drivers in the weight loss journey. However, what diet is most effective, remains a matter of continued scientific and popular debate. Low energy diets (LEDs), very low energy diets (VLEDs), low-­carbohydrate, low-fat and ­intermittent fasting are a few ­examples of the available alternatives. Certainly, individual preferences and metabolic needs should be taken into account, but ­compliance seems nevertheless to be the most important factor in determining magnitude of weight loss, at least in the short-term (7).

Several myths have surrounded the use of VLEDs (diets providing <800 kcal/day), including a larger loss of muscle mass, reduction in resting metabolic rate and weight regain compared with less restricted LEDs (diets providing > 800 kcal/day). These myths have been disproved by us and others (8, 9), and there is even evidence that it may be easier to lose weight rapidly with a VLED, as a larger number of individual seems to reach weight loss targets with VLEDs vs LEDs (9). This may derive from the fact that results (i.e. loss in body mass) are seen much faster, which may work as a motivational factor and also potentially due to a lesser degree of the commonly described increase in hunger seen with other dietary weight loss approaches (8). This is important as increased hunger may contribute to the high attrition rate seen in weight loss attempts.

Long-term weight loss maintenance

However, the main challenge in obesity management is not just weight loss, as the majority can do it with a variety of approaches. It is the maintenance of a reduced body weight in the long-term that is challenging. Less than 20% of individuals who have attempted to lose weight are able to maintain a 10% reduction of baseline weight over one year (1) and the expected average weight loss after a 5 year follow up, when including all possible combinations of lifestyle approaches, has been shown to be only 3 kg (10).

The reasons for the high relapse rate in obesity treatment are complex and not fully understood, but a combination of reduced motivation and compliance with the intervention (11), together with several biological adaptations to the weight reduced state that try to bring body weight back to its original state (12) are likely to be involved (see table 1).

Table 1. Potential physiological adaptations to the weight-reduced state

Table 1. Potential physiological adaptations to the weight-reduced state

These responses include an increase in hunger (driven by changes in our ­appetite control system towards increased secretion of the hunger-hormone ghrelin), despite significantly reduced total energy expenditure (TEE) and changes in substrate oxidation which favor fat deposition (2). The reduction in TEE arises from a decrease in both resting and non-resting energy expenditure, but  the reduction in exercise induced-energy expenditure, due to increased efficiency, seems to be particularly important (13). A 10% weight loss has been shown to result in an 18% reduction in TEE, a decrease that is almost twice as large as expected, given the magnitude of weight lost, a mechanism known as adaptive thermogenesis (meaning that the body goes into a saving or hibernation mode) (13). Unfortunately these adaptive response are not transitory and seem to persist in the long-term (14, 15).

Although a sustained weith loss is difficult to attain, the patients should not surrender to the inevitability of weight regain. It is possible to lose weight and maintain it in the long-term with conservative approaches, as proved by the members of the Weight loss Control Register in the States (entry criteria – to have lost at least 14 kg and maintained it for at least one year) (16). Research done in this group of successful individuals (average weight loss 30 kg maintained for an average of 5.5 years (16)) has shown that the majority lost weight with both diet and exercise and that different dietary approaches were used (16). Behavioral strategies used by this group include daily self-weighing (17), eating breakfast every day (18), having a consistent low energy (average 1200 and 1600 kcal/day in women and men, respect­ively), low-fat diet (same on weekdays and weekends, working days and holidays) (16, 19) and exercising regularly (1 hour/day, mainly walking) (16). However, even in this successful group, weight regain is common and has been shown to be associated with a reduction in the frequency of self-weighing (17), an increase in percentage energy from fat and a reduction in physical activity levels (20).

Figur 1. Several biological adaptions to the weight reduced state try to bring body weight back to its origninal state.  Fra Melby et al, Compensatory mechansims. Nutritents 2017

Figur 1. Several biological adaptions to the weight reduced state try to bring body weight back to its origninal state. Fra Melby et al, Compensatory mechansims. Nutritents 2017

Concluding remarks

Maintaining a weight reduced state requires a daily fight against sustained physiological adaptations with increased hunger and reduced energy expenditure. No wonder that it is so difficult and that so few succeed. Having to ­consistently eat less, when feeling hungrier, to match a ­sustained reduced total energy ­expenditure (on average 400 kcal lower than what would be expected in an ­individual of similar weight and body ­composition who has never lost weight (15)) is not an easy task. The patient with obesity who is struggling to maintain weight loss should therefore not be regarded as an uncompliant sedentary overeater. This patient has to fight every day for the rest of his life with strong biological adaptations, which try to upregulate body weight. Health professionals should congratulate the few who are able to maintain weight loss in the long-term for their accomplishment and support those who are struggling to ­implement recommended lifestyle changes. More importantly, we need to recognize obesity as a chronic condition and, as such, requiring lifelong support.


Referanser

  1. Kraschnewski JL, Boan J, Esposito J, Sherwood NE, Lehman EB, Kephart DK, et al. Long-term weight loss maintenance in the United States. Int J Obes. 2010;34(11):1644-54.
  2. Cornier MA. Is your brain to blame for weight regain? Physiol Behav. 2011;104:608-12.
  3. Bray GA, Kim KK, Wilding JPH. Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obes Rev. 2017;18(7):715-23.
  4. World Health Organization. Obesity and overweight (Fact sheet N°311) 2013 [
  5. Midthjell K, Lee CMY, Langhammer A, Krokstad S, Holmen TL, Hveem K, et al. Trends in overweight and obesity over 22 years in a large adult population: the HUNT Study, Norway. Clinical Obesity. 2013;3(1-2):12-20.
  6. Blackburn G. Effect of degree of weight loss on health benefits. Obes Res. 1995;3(Suppl 2):211s-6s.
  7. Dansinger ML, Gleason JA, Griffith JL, Selker HP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA. 2005;293(1):43-53.
  8. Coutinho SR, With E, Rehfeld JF, Kulseng B, Truby H, Martins C. The impact of rate of weight loss on body composition and compensatory mechanisms during weight reduction: A randomized control trial. Clin Nutr. 2017.
  9. Purcell K, Sumithran P, Prendergast LA, Bouniu CJ, Delbridge E, Proietto J. The effect of rate of weight loss on long-term weight management: a randomised controlled trial. The lancet Diabetes & endocrinology. 2014;2(12):954-62.
  10. Anderson JW, Kons EC, Frederich RC, Wood CL. Long-term weight-loss maintenance: a meta-analysis of US studies. Am J Clin Nutr. 2001;74(5):579-84.
  11. Elfhag K, Rossner S. Who succeeds in maintaining weight loss? A conceptual review of factors associated with weight loss maintenance and weight regain. Obes Rev. 2005;6(1):67-85.
  12. MacLean PS, Bergouignan A, Cornier MA, Jackman MR. Biology’s response to dieting: the impetus for weight regain. Am J Physiol Regul Integr Comp Physiol. 2011;301(3):R581-R600.
  13. Leibel RL, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. The New England Journal of Medicine. 1995;332:621-8.
  14. Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, et al. Long-term persistence of hormonal adaptations to weight loss. New Eng J Med. 2011;365:1597-604.
  15. Rosenbaum M, Hirsch J, Gallagher DA, Leibel RL. Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight. Am J Clin Nutr. 2008;88(4):906-12.
  16. Hill JO, Wyatt H, Phelan S, Wing R. The National Weight Control Registry: is it useful in helping deal with our obesity epidemic? Journal of nutrition education and behavior. 2005;37(4):206-10.
  17. Butryn ML, Phelan S, Hill JO, Wing RR. Consistent self-monitoring of weight: a key component of successful weight loss maintenance. Obesity (Silver Spring, Md). 2007;15(12):3091-6.
  18. Wyatt HR, Grunwald GK, Mosca CL, Klem ML, Wing RR, Hill JO. Long-term weight loss and breakfast in subjects in the National Weight Control Registry. Obes Res. 2002;10(2):78-82.
  19. Gorin AA, Phelan S, Wing RR, Hill JO. Promoting long-term weight control: does dieting consistency matter? Int J Obes Relat Metab Disord. 2004;28(2):278-81.
  20. McGuire MT, Wing RR, Klem ML, Lang W, Hill JO. What Predicts Weight Regain in a Group of Successful Weight Losers? J Consult Clin Psychol. 1999;67(2):177-85.
Norsk Indremedisinsk Forening
Ansvarlige redaktører:
Ole Kristian H. Furulund, Stephen Hewitt
Opphavsrett: ©Norsk Indremedisinsk Forening
Følg NYI på: Facebook
Webmaster og design: www.drd.no