Physicians' Academy for Cardiovascular Education

RCT refutes common believe that gradual weight loss has longer lasting effect than crash diet

Purcell et al., Lancet Diabetes & Endocrinology 2014

 

The effect of rate of weight loss on long-term weight management: a randomised controlled trial


Katrina Purcell, Priya Sumithran, Luke A Prendergast, et al.
The Lancet Diabetes & Endocrinology, Early Online Publication, 16 October 2014
doi:10.1016/S2213-8587(14)70200-1
 

Background

The increasing prevalence of obesity now poses a major health problem in both low-income and high-income countries [1]. Dietary weight loss is generally not maintained on the long run [2,3]. Although it is unclear what is the best method to achieve and maintain weight loss, international guidelines recommend gradual weight loss for the treatment of obesity [4-6]. This most likely reflects the belief that gradual weight loss allows more time to change the bad social habits that often underlie obesity.
This widespread believe in the superiority of gradual over rapid weight loss has recently been challenged [7,8], and scientific evidence does not support this superiority of a gradual approach [9]. This study aimed to investigate whether the rate of weight loss affects the rate of weight regain in a two-phase, randomised, dietary intervention trial. Also, it was studied whether weight loss-induced changes in circulating appetite-mediating hormones and subjective appetite are affected by the rate of weight loss. In phase 1, 200 obese individuals (BMI: 30.0-45.0 kg/m2) were randomised to either a rapid (12 weeks) or a gradual (36 weeks) weight loss programme, aiming to loose 15% of weight. In phase 2, patients were instructed to follow an individualised diet for weight maintenance for 144 weeks, and had regular individual sessions with a dietician.
 

Main results

  • 179 (89.5%) participants completed phase 1. Individuals more often discontinued the gradual (n=18, 18%) than the rapid (n=3, 3%) weight loss programme.
  • 76 out of 94 (81%) who completed phase 1 in the rapid programme achieved 12.5%, as compared to 53 out of 85 (62%) in de gradual weight loss programme (P=0.009).
  • By week 144 of phase 2, participants in the gradual programme had regained on average 10.4 kg (95%CI: 8.4-12.4, 71.2% (58.1-84.3) of lost weight regained) while participants in the rapid weight loss group regained on average 10.3 kg (8.5-12.1, 70.5% (57.8-83.2) of lost weight regained).
  • 3-β-hydroxybutyrate (related to ketone concentration in blood, suppressing appetite) was measured at 5% and 10% weight loss during phase 1, and found to be significantly higher in the rapid weight loss group than in the gradual programme, while no significant difference was seen at the end of phase 1.
  • Leptin levels reduced more with rapid weight loss than gradual weight loss in phase 1. Leptin concentrations increased in both groups in phase 2. Leptin levels did not differ from baseline in either group at week 48, but they were significantly increased at week 144 in both groups.
    Irrespective of initial rate of weight loss, participants who regained at least 75% of lost weight by week 144 (n=45) showed large increases in leptin above baseline concentrations.
  • Mean fasting ghrelin concentrations increased after weight loss and remained high during phase 2, without significant differences between the two weight loss programmes.
  • Hunger ratings did not increase during phase 1 in either group, while at weeks 48 and 144 of phase 2 it increased significantly in rapid weight loss participants.

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Conclusion

This randomised study shows that, contrary to a widely-held belief, weight regain does not occur quicker after rapid weight loss. Regain of lost weight was similar in a rapid and a gradual weight loss intervention. Achievement of a weight loss target of 12.5% was more likely in a rapid weight loss programme, and fewer individual withdrew from a rapid as compared to a gradual weight loss programme. Hormonal measurements confirm that physiological adaptations to weight loss are long lasting and suggest that a strategy to suppress hunger after weight loss and therefore to prevent weight regain may be useful.
 
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References

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