1-9 RANDOMIZED COMPARISON OF DIETS FOR MAINTAINING OBESE SUBJECTS’ WEIGHT AFTER MAJOR WEIGHT LOSS:
Ad-lib, low fat, high carbohydrate vs fixed energy intake Obese patients inevitably lose weight when they keep strictly to an energy restricted diet, but long term results of energy restriction (so called calorie counting) are modest. Only about 10% of subjects maintain a weight loss of over 5 kg after 5 years. A high fat diet plays a crucial role in the development and maintenance of obesity. The apparent role of dietary fat in obesity has led to the evaluation of ad-lib, high carbohydrate diets.
This study compared efficacy of two different weight maintenance programs. Conclusion: Ad-lib, low fat, high carbohydrate diet was superior to fixed energy intake diet in maintaining weight loss.

STUDY

1. 1. Entered 43 obese patients (body mass index—27-40; mostly women) who were otherwise healthy.
2. 2. Placed on a low energy diet for 8 to 17 weeks to reduce weight.
3. 3. After weight loss occurred, randomized to : 1) Ad-lib, low fat, high carbohydrate diet (20%-25% of energy from fat; at least 55% from carbohydrate) or 2) fixed energy intake diet. (See p 30 for description)—1 year

RESULTS

• 1. At baseline, after the weight reduction phase, patients had lost a mean of about 14 kg.
• 2. For those completing the 1 year trial (n=28; 75%) the mean weight change from baseline:
• 6 Mo. 1 year
• Ad-lib -2.3 kg +0.3 kg
• Fixed energy +0.5 kg +4.1 kg
• 3. For those completing the one year trial, 65% of the ad-lib group, and 25% of the fixed energy group had maintained a weight loss of over 5 kg.

DISCUSSION

1. A low fat, high carbohydrate diet consumed ad-lib was superior to a more traditional fixed energy intake diet in maintaining weight loss.
2. The mechanism by which a low fat, high carbohydrate diet prevents relapse to a positive energy balance and weight regain may be both by reducing energy intake and by increasing energy expenditure. The effect on appetite seems to be predominant.
3. Levels of body fat and obesity are positively associated with dietary fat content. Obese persons generally consume a diet with a higher fat content than do lean persons.
4. Carbohydrate has a higher satiating effect than fat.
5. "For nutritional public health policy, our results support the theory that a low fat diet could contribute to preventing obesity."

CONCLUSION

An ad-lib, low fat, high carbohydrate diet was superior to fixed energy intake for maintaining weight after a major weight loss.
BMJ January 4, 1997; 314: 29-33 Original investigation, from Royal Veterinary and Agriculture University, Copenhagen, Denmark

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