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Maintaining resting metabolic rate during fat loss is vital

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An article in the journal Obesity (2016) reports that over 50% of contestants in US reality TV show The Biggest Loser at 6 year follow up had regained a ‘substantial amount’ of the weight they lost during the 30 week contest.

The authors explain that weight loss leads to a reduction in the body’s resting metabolic rate (RMR) – the body adapts to carrying less fat around and needs less calories to stay alive. The average fat loss in the group was 104 pounds, but the average regain in fat by 6 year follow up was 77 pounds. They also lost an average of 24 pounds of muscle (a lot of metabolically active tissue), and only regained 13 pounds of this. The RMR dropped on average by 611 kcals by the end of the 30 week programme, and dropped further by 93 kcals by the 6 year follow up. The reasons for this further decline in RMR are not clear in the study. There is no information on the exercise the participants were doing between the end of the contest and the 6 year follow up, but perhaps if they had been exercising enough to build their muscles back up then the RMRs may have increased again rather than decreased.

The main points from the Obesity article are :-

  • restrictive diets lead some people to be preoccupied with food, triggering overeating
  • decreased RMR and loss of lean mass (muscle) leads to post diet weight rebound
  • the body tries to restore lost weight as a defensive mechanism

On the positive side, The National (US) Weight Control Registry state that long term weight loss is achievable, and define successful weight loss as a 10% reduction in weight sustained over a year. This 10% target is effective as it produces meaningful reduction in risk factors for heart disease and type 2 diabetes.

Successful weight loss maintenance is associated with :-

  • high levels of physical activity (at least one hour/day of somewhat hard activity) = 2,545 cals/week for women, 3,293 cals/week for men
  • consistent low calorie diet
  • consistent eating of breakfast
  • frequent monitoring of weight
  • maintaining consistent diet during the week and at weekends
  • decreased periods of uncontrolled eating
  • development of emotional regulation skills to control overeating

I would add that training to increase or maintain muscle mass is paramount to limit losses in RMR simultaneous with fat loss. Two to three times a week of heavy resistance training would be ideal. Once a 10% weight loss has been sustained for a year, then a further 10% could be the target for the following year, but this would only be achievable by keeping your RMR as high as possible with exercise.

Lisa :)

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