Eight-Year Weight Losses with an Intensive Lifestyle Intervention: The Look AHEAD Study

Article Summary Assignment for

“Eight-Year Weight Losses with an Intensive Lifestyle Intervention:

The Look AHEAD Study”

Obesity (Silver Spring). 2014 Jan;22(1):5-13. doi: 10.1002/oby.20662. Eight-year weight losses with an intensive lifestyle intervention: the look AHEAD study. Look AHEAD Research Group.

The objective of the Look AHEAD study is to evaluate the 8 year weight loss results with Intensive Lifestyle Intervention (ILI) or Diabetes Support and Education (DSE). The study’s population were 5,145 men and women, aged 45-76 years old with Type 2 Diabetes Mellitus and BMI≥25 kg/m2 (or ≥27 kg/m2 if taking insulin); passing exercise and behavioral adherence tests. Year-8 had a retention rate of 94.0%; as 89.9% and 88.3% of ILI and DSE participants, respectively, completed the 8-year outcomes assessment (p=0.077). Participants were randomly assigned to either ILI or DSE (random-control trial).

In year 1 and 2-8 ILI and DSE had different interventions adapted from the Diabetes Prevention Program (DPP). ILI participants received interventions for an average of ≥7% weight loss, and groups of 10-20 participants were in 60-75 minute group sessions for the first three weeks of the month; for the fourth week of the month, participants met individually with their interventionist for 20-30 minutes. In months 7-12 of the first year, participants had two group meetings, and one interventionist meeting. Participants’ prescribed diet was 1200-1800 kcal/day, consisting of ≤30% and ≥15% from fat and protein, respectively. Participants were given structured meal plans and replacements (liquid shakes and meal bars); from weeks 5-12, participants were instructed to replace one meal and snack daily. Participants were prescribed ≥175 minutes/week moderate intense physical activity, and after month 6, increasing up to ≥200 minutes/week physical activity. In years 2-8, ILI participants had lifestyle counseling and encouraged to restrict calories, continue physical activity and use meal replacements. Members weighed in and reviewed diet and activity records during years 2-8 in a monthly group meeting. During years 1-4, DSE participants discussed diet, physical activity and social support during three 1-hour group meetings each year. Participants then had one meeting per years 5-8. DSE did not offer behavioral intervention information to participants, whereas ILI did.

Data collected included weight measured at baseline and annually, physical activity (through a questionnaire) and reports on participant’s engagement in “long-term weight control activity,” which were increasing physical activity, monitoring body weight, reducing calorie and fat intake and using meal replacements. The study statistically analyzed the differences between the ILI and DSE groups in weight changes over the 8 years using a mixed effects of covariance, including the baseline weight, clinical center and treatment arm. The analyses grouped participants according to the intervention assignment independent of subject’s adherence to the study (intention to treat principle). Participants were compared using generalized estimation equations (GEE) according to their 5% and ≥10% categorical weight loss. Analysis of covariance and GEE was used to compare behavioral outcomes. A mixed effect analysis of covariance was used to compare weight loss with gender, age, and race/ethnicity.

The main findings of the study state that ILI participants lost ±SE) of 8.5±0.2% of initial weight, compared with 0.6±0.2% for DSE (p<0.001). More ILI than DSE participants lost ≥5% of initial weight (68.0% vs. 13.3%, p <0.001), as well as ≥10% (37.7% vs. 2.9%, p<0.001). The participants’ baseline characteristics in ILI and DSE did not differ significantly.At all years, ILI participants lost significantly more weight than DSE participants. At year 1, more non-Hispanic white participants lost significant weight; however, at years 4 and 8, there was not a significant difference amongst races. ILI participants reported more weeks in practicing long-term weight control activities. 825 ILI participants lost ≥10% of weight at year 1, of those 39.3% continued to achieve a ≥10% weight loss per annum. Participants in both ILI and DSE reported 860 kcal/week physical activity expenditure, yet ILI participants showed greater results in increasing in caloric expenditure in the first year (only) and number of weeks practicing long-term weight control activity. Of the 825 ILI participants, (39.3%) achieved a ≥10% loss at year 8, 213 (25.8%) a loss of 5 to <10%, 171 (20.7%) a loss of 0 to <5%, and 117 (14.2%).

For over 8 years, ILI created a weight loss intervention in an ethnically diverse population. ILI showed that weight loss for African American was one of the largest amount in literature. Most participants seemed to lose with the most weight in the first year, however ILI showed continuous weight loss after the first year. Look AHEAD showed that ILI participants lost 4.7% of initial body weight by year 8, compared to DSE participants who lost 2.1%. In addition, 50% ILI participants lost ≥5% of initial weight, and 26.9% lost ≥10%. However, 32% of ILI participants did not 5% of weight in first year and of these participants, only 34.5% achieved 5% of weight loss by the end of year 8. In conclusion, Look AHEAD demonstrated that a long time lifestyle intervention demonstrates greater weight loss results.

Strengths of Look AHEAD is that it is the longest study in literature measuring weight loss using lifestyle intervention and using a large diverse sample size, allowing for comparison between age, gender and ethnicity. In addition, to weight loss, the study offers data on physical activity and calorie intake. Participants were randomly assigned to either ILI or DSE intervention, therefore bias is minimized during participant’s assignment to groups. Yet, a weakness of this study may be that the DSE and ILI interventionists (RD, MD, Exercise specialists and psychologists) were employed by the Look AHEAD and aware of the study’s efforts in encouraging weight loss and may have different results than an independent health professionals. A confounding factor could be that each participants may have a different response of diabetes and aging, affecting their weight loss results.

Participants undergoing bariatric surgery were not excluded from this study, which may have affected their weight loss results of these individuals in comparison to participants that did not undergo bariatric surgery. Another weakness may be the use of replacement meals (offered in ILI) to encourage weight loss results. In real life situations, participants may not purchase these meal replacements; therefore, their weight loss results in the study may not accurately represent a real-life situation. Future directions for this field of research would be examining the effects of ILI and DSE on participants after the study has culminated (year 8). This research could demonstrate the long-term effects of weight loss as a result of DSE or ILI. In addition, the research could further look into ILI participants’ behavioral changes in their weight loss efforts, as part of the ILI interventionists were psychologists using Cognitive Behavioral Therapy (CBT).