TOPLINE

Including a patient's spouse or partner in a weight-loss program — even for just half the sessions, with no requirement that they change anything — helped that partner lose meaningful weight over two years. At 24 months, partners who took part lost about 2 kg more than partners who were uninvolved, and were roughly twice as likely to hit a clinically meaningful 5% weight loss (37% vs. 20%).

METHODOLOGY

• Partners often lose weight alongside patients even without joining a behavioral weight management program (a "ripple effect"), but it wasn't clear whether actively bringing them into the program produces a bigger effect than that ripple alone.
• In a secondary analysis of a randomized controlled trial, 231 cohabiting couples — each with one partner eligible for weight management (BMI of 27-29.9 with a weight-related comorbidity or BMI ≥ 30) and a cohabiting romantic partner (BMI ≥ 18.5) — were randomly assigned to either a partner-assisted intervention (n = 115) or a participant-only intervention (n = 116); most partners were male (63%) and White (88%), with a mean age of 48.3 years and a mean baseline BMI of 32.0.
• The patient enrolled for weight loss participated in a 24-month evidence-based group weight-management program: a 6-month weight-loss phase, a 12-month weight-loss maintenance phase, and a 6-month no-intervention phase; partners in the partner-assisted group attended 6 of 13 weight-loss group sessions, without being required to change their own behavior or lose weight.
• Partners in the participant-only group did not attend any intervention sessions or calls, serving as the untreated comparison group.
• Partner weight and self-reported caloric intake were tracked over 24 months and compared between the two groups.

TAKEAWAY

• At 24 months, partners in the partner-assisted group lost significantly more weight than those in the participant-only group (-2.5 vs -0.4 kg; P = .008).
• A higher proportion of partners in the partner-assisted group than in the participant-only group achieved at least a 5% weight loss from baseline at all follow-up timepoints: 24% vs 15% at 6 months, 30% vs 21% at 12 months, 34% vs 19% at 18 months, and 37% vs 20% at 24 months.
• Differences were larger among partners with baseline BMI ≥ 27 (estimated mean difference, -2.9 kg; P = .003).
• No significant between-group difference was seen in changes from baseline in self-reported caloric intake at 24 months (P = .07).

IN PRACTICE

"Participation in behavioral weight management as a supportive partner and not as a target for weight loss can result in clinically meaningful weight loss among partners over time, especially among those with elevated BMI. Partners benefited from the intervention even though they received a lower dose, attending only a subset of sessions and calls," the authors wrote. "Considering that weight loss was greater when restricting to partners who also met BMI criteria for behavioral weight management, it may be that disease‐oriented approaches (where the partner is a co‐target of the intervention) are most effective when both the index participant and partner have elevated BMIs," they added.

SOURCE

The study was led by Kristen E. Gray, Health Systems Research, VA Puget Sound Health Care System, Seattle. It was published online in Obesity Science & Practice.

LIMITATIONS

The study population was relatively homogeneous — predominantly non-Hispanic White, high socioeconomic status, and heterosexual — limiting generalizability to other populations. A significant dropout occurred, with only 73% of partners providing weight outcomes at 24 months. Partner physical activity was not measured, so its role in weight loss could not be assessed.

DISCLOSURES

The study was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases. Some authors were supported by a Department of Veterans Affairs Research Career Scientist Award and a Career Development Award from the Health Systems Research service of the Department of Veterans Affairs. Some authors reported having consulting engagements with pharmaceutical or food industry companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.