- Click here for explanation of classification scheme.

The objective was to examine the long-term weight-loss maintenance of individuals completing a structured weight-loss program.

1. Study conducted in the US.

2. Subjects participated in a structured weight loss program instead of self-help activities.

3. Follow-up weights with variance estimates must have been available for >=2 yr.

Studies that did not provide specific follow-up weight-loss information.

Recruitment

A literature search using MEDLINE between 1970-1999, review articles, and references within articles identified through MEDLINE.  Search terms not mentioned.

Design

Meta-Analysis.

Blinding Used (if applicable)

Not applicable.

Intervention (if applicable)

Follow-up weights were assessed at 1, 2, 3, 4, and 5 years.

Statistical Analysis:

Estimates of diet, sex and follow-up at each year were made using the fixed-effect model.  Homogeneity of results across studies was evaluated and the 95% confidence intervals were calculated.  Values are weighted means (+ 95% CI) for all subjects.

Timing of Measurements

For each study, summary results of all reported values and additional relevant study attributes were recorded, coded, and tabulated for analysis.

Dependent Variables

• The primary effect estimate was calculated as follows:

Weight-loss maintenance (kg) = initial body weight- body weight at follow-up

• Other outcome variables:

Weight-loss maintenance (%) = (weight loss maintenance/average initial weight loss) x 100

Reduced weight (%) = (weight loss maintenance/ average initial body weight) x 100

Independent Variables

Control Variables

Initial N: 31 separate published reports met the initial criteria. 2 reports were eliminated due to lack of specific follow-up weight-loss information.

Final N: 29 studies analyzed

Age: subjects' mean age was 45 y

Ethnicity:  not mentioned

Other Relevant Demographics:

• sample size ranged from 6 to 508 subjects
• majority of the studies included both men and women
• 13 studies used VLED (very-low-energy diets), and 14 used HBDs (hypoenergetic balanced diets)
• median length of treatment for VLED was 22 wks and for HBDs was 12 wk.
• average initial body weights for women ranged from 74 to 121 kg
• average initial weight losses in women ranged from 3.5 to 37.9 kg; average initial weight losses in men ranged from 6.2 to 44.2 kg.
• median percentage of subjects completing the weight-loss program was 82%.

Anthropometrics

Location:  Only U. S. studies were evaluated

 

	VLED	HBD
Individuals at 4 or 5 yr follow-up (%)	55.4%	79.7%
Weight loss Maintenance, kg (95% CI)	7.1 kg (6.1-8.1)	2.0 kg (1.5-2.5)
Weight loss Maintenance, % (95% CI)	29% (25%-33%)	17% (13% 22%)
Reduced Weight, % (95% CI)	6.6% (5.7%-7.5%)	2.1% (1.6%-2.7%)

Other Findings:

29 studies met the criteria for analysis. Successful very low energy diets (VLED) were associated with significantly greater weight-loss maintenance than were successful hypoenergenic balanced diets (HBDs) at all years of follow-up.

Weight-loss maintenance did not differ significantly between women and men.

6 studies reported that groups who exercised more had significantly greater weight loss maintenance that did those who exercised less.

Weight loss maintenance at 4 or 5 years after a structured weight-loss program averages 3.0 kg or 23% of initial weight loss, representing a sustained reduction in body weight of 3.2%. 

Individuals who particpated in a VLED program or lost > 20 kg had a weight-loss maintenance at 4 or 5yr of 7kg or 29% of initial weight loss, representing a sustained reduction in body weight of 6.6%.

Although success in weight loss maintenance has improved over the past decade, much more research is required to enable most individuals to sustain the lifestyle changes in physical activity and food choices necessary for successful weight maintenance.

Industry:

Health Management Resources Other:

The important point from this meta-analysis is that an initial greater weight loss results in a greater percentage of weight loss maintenance long term.  Although follow-up information was available on subjects for several years, the intervention periods were quite short (VLED:  22 weeks, HBD:  12 weeks).  The interpretation of these results should take into consideration that the true effect of a weight-loss intervention could be best assessed in a long-term, randomized controlled clinical trial.