Four-year weight losses in the Look AHEAD study: factors associated with long-term success

Abstract

This report provides a further analysis of the year 4 weight losses in the Look AHEAD (Action for Health in Diabetes) study and identifies factors associated with long-term success. A total of 5,145 overweight/obese men and women with type 2 diabetes were randomly assigned to an intensive lifestyle intervention (ILI) or a usual care group, referred to as Diabetes Support and Education (DSE). ILI participants were provided approximately weekly group or individual treatment in year 1; continued but less frequent contact was provided in years 2-4. DSE participants received three group educational sessions in all years. As reported previously, at year 4, ILI participants lost an average of 4.7% of initial weight, compared with 1.1% for DSE (P < 0.0001). More ILI than DSE participants lost ≥ 5% (46% vs. 25%, P < 0.0001) and ≥ 10% (23% vs. 10%, P < 0.0001) of initial weight. Within the ILI, achievement of both the 5% and 10% categorical weight losses at year 4 was strongly related to meeting these goals at year 1. A total of 887 participants in ILI lost ≥ 10% at year 1, of whom 374 (42.2%) achieved this loss at year 4. Participants who maintained the loss, compared with those who did not, attended more treatment sessions and reported more favorable physical activity and food intake at year 4. These results provide critical evidence that a comprehensive lifestyle intervention can induce clinically significant weight loss (i.e., ≥ 5%) in overweight/obese participants with type 2 diabetes and maintain this loss in more than 45% of patients at 4 years.

Figure 1

Mean (± SE) percent reduction in initial weight in the Diabetes Support and Education (DSE) and Intensive Lifestyle Intervention (ILI) groups over 4 years. Differences between groups were significantly different (p < 0.0001) at all 4 years. Mean weight losses for DSE participants at each of the 4 years were 0.8 ± 0.1, 1.1 ± 0.1, 1.2 ± 0.2, and 1.3 ±0.2 kg, respectively. Corresponding values for ILI were 8.7 ± 0.2, 6.5 ± 0.2, 5.3 ± 0.2, and 4.9 ± 0.2 kg, respectively.

Figure 2

Percentage of participants in the Diabetes Support and Education (DSE) and Intensive Lifestyle Intervention (ILI) groups who at year 4 met different categorical weight losses (e.g., > 0%, ≥ 5%, ≥ 10%, etc.). The weight loss and regain categories are cumulative. For example, the 74% of ILI participants who lost > 0% of initial weight includes the 46% who lost ≥ 5%. The 26% of ILI participants who gained ≥ 0% above their baseline weight includes the 8% who gained ≥ 5%. A significantly greater percentage of ILI than DSE participants met each of the categorical weight losses shown (all p’s < 0.0001), whereas a significantly smaller percentage met the weight regain categories (both p’s < 0.001)

Figure 3

A. Weight loss trajectories over 4 years in the 887 participants in the Intensive Lifestyle Intervention (ILI) who, at year 1, lost ≥ 10% of initial weight. The figure shows the number of participants who, at year 4, maintained a loss of 10% or more of initial weight (N = 374), of 5.0–9.9% (N = 251), or of 0–4.9% (N = 174) or who gained above their baseline weight (N = 88). The percentages shown in parentheses are based on the sample size for the subgroup. Thus, the 374 of 887 participants who maintained a 10% loss at year 4 comprised 42.2% of this subgroup of participants. B. Weight loss trajectories over 4 years in the 702 ILI participants who, at year 1, lost 5.0–9.9% of initial weight. The four categories of weight change that these participants achieved at year 4 are presented in the same manner as in Figure 3A. C. Weight loss trajectories over 4 years in the 729 ILI participants who, at year 1, lost < 5% of initial weight. The four categories of weight change that these participants achieved at year 4 are presented in the same manner as in Figures 3A and 3B.

Figure 4

A. Mean number of total treatment contacts per year (for years 2–4) in ILI participants who had lost ≥ 10% at 1 year. Participants are shown based upon their weight change category at year 4: lost ≥ 10% of initial weight (N = 374), 5.0–9.9% (N = 251), or 0–4.9% (N = 174) or gained above baseline weight (N = 88). Participants who maintained a 10% loss had significantly more contacts per year than those who maintained a loss of 0–4.9% or gained above baseline. B. Self-reported weekly calorie expenditure from physical activity in year 4 for ILI participants who had lost ≥ 10% at year 1 and were in the subset of participants who completed the Paffenbarger Activity Questionnaire at year 4. Participants are shown based upon their weight change category at year 4: lost ≥ 10% of initial weight (N =186), 5.0–9.9% (N = 120), or 0–4.9% (N = 79) or gained above baseline weight (N = 45). Participants who had a 10% loss reported significantly greater energy expenditure from physical activity than participants in the three other weight categories. C. Self-reported daily calorie intake in year 4 for the ILI participants who had lost ≥ 10% at 1 year and were in the subset of 502 ILI participants who completed the Food Frequency Questionnaire at year 4. Participants are shown based upon their weight change category at year 4: lost ≥ 10% of initial weight (N = 209), 5.0–9.9% (N = 140), or 0–4.9% (N = 103) or gained above baseline weight (N = 50). Participants who had a 10% loss at year 4 reported a significantly lower calorie intake than those who gained above their baseline.