The economics of weight loss, with Rebecca Diamond and Claer Barrett

Episode Summary

Executive Summary: The episode explores why obesity is more strongly linked to lower income among women than men, and how GLP-1 drugs may change that relationship. Economist Rebecca Diamond’s study suggests the drugs can raise women’s employment and partnership rates, potentially through reduced discrimination or increased confidence, while also raising policy questions about inequality, health spending, and the broader economic effects of widespread weight loss.

Main Topics: Women, income, and obesity (Priority: 5/5): The discussion opens with the finding that obesity is much more strongly concentrated among poorer women than poorer men, suggesting the income-weight relationship is not driven by poverty alone and may operate differently by gender. Why weight affects women differently (Priority: 4/5): Claire Barrett and Sumaya Keynes discuss mechanisms including time scarcity, unpaid care work, convenience food, and the social pressure on women to prioritize others over their own health. GLP-1 drugs and economic mobility (Priority: 5/5): Rebecca Diamond explains her research on whether GLP-1 weight-loss drugs change employment and partnership outcomes for women, using future users as a control group. Discrimination versus productivity (Priority: 4/5): The conversation weighs whether gains in employment are due to reduced weight-based discrimination or to improved confidence, behavior, or focus after weight loss. Methodology and causal identification (Priority: 4/5): Diamond defends her design by comparing GLP-1 users to people who want the drugs but have not yet started, and checking for pre-trends across many outcomes. Policy, inequality, and public spending (Priority: 5/5): The final section debates whether governments should subsidize GLP-1s, given potential labor-market gains, health benefits, high drug costs, and the possibility of widening inequality. Consumer spending and broader economic effects (Priority: 3/5): Claire Barrett adds that GLP-1s are changing food purchases and household budgets, hinting at wider impacts on retail, grocery, and consumer demand.

Key Arguments: The obesity-income gradient is far stronger for women than men, implying that social and economic mechanisms beyond simple diet access are at work. Women face distinct time and care burdens that make convenience foods and neglect of self-care more likely, which may help explain the gender gap in obesity. Education and place-based interventions can reduce obesity, showing socioeconomic status does affect weight. Obesity can also reduce women’s income through discrimination in hiring, promotion, and public-facing jobs. GLP-1 use is associated with large rises in women’s employment and partnership rates, especially among those starting from unemployment or singleness. The strongest effects appear only after one to two years, which Diamond argues is more consistent with weight loss than with a short-lived life-reorientation event. Some effects could still reflect confidence or productivity changes, but the pattern is suggestive of discrimination at the hiring/matching margin. Policy should consider both health and economic gains, but subsidies may widen inequality if only higher-income people can afford the drugs. Claire Barrett argues the drugs may pay for themselves personally through improved health, longer working life, and lower food spending. The broader economy is already seeing shifts in supermarket spending and food choices, though aggregate effects are still muted in the UK because uptake remains limited.

Data Points: Obesity rate gap among American women: 14 percentage points - Difference between the poorest third and richest third of American women. Obesity rate gap among American men: under 1 percentage point - Income-based obesity gap for men is much smaller than for women. Employment increase after GLP-1 use: 29 percentage points - Increase in employment rate among women who were not employed when they began GLP-1 drugs, measured about two years later. Partnership increase after GLP-1 use: 29 percentage points - Increase in probability of being partnered among women who were single at baseline, over the same horizon. Time to peak effects: about 2 years - Employment and partnership effects build gradually and peak roughly two years after starting treatment. Onset of effects: about 6 months - Employment effects begin to rise around six months after GLP-1 initiation. Pre-trend window tested: 3 years before adoption - Diamond tests whether treated and control groups diverged prior to starting GLP-1s. Number of outcomes tested: about 20 - Diamond says she checked multiple outcomes for differential pre-trends. Men leaving prior spouses/partners: 12 percentage point increase - The only clear male effect reported in the smaller male sample. Personal monthly drug cost: £200–£250 a month - Claire Barrett estimates her own cost of using GLP-1 drugs. Personal total spending on drugs: about £5,000 - Claire Barrett’s cumulative spending on treatment. Cost per stone lost: about £1,000 per stone - Claire Barrett’s rough estimate of the investment per unit of weight lost. UK grocery spending reduction: £800 million a year - Estimate from a World Panel study on reduced supermarket spending among GLP-1 users in the UK.

Pivotal Quotes: "I find a pretty massive increase in how likely they are to be employed about two years later." — Rebecca Diamond: Summarizing the main employment result for women who were not employed when they started GLP-1 treatment. "It’s only after a year to two years where the effect really starts to kick in, exactly on the horizon where the weight loss has really occurred." — Rebecca Diamond: Explaining why the timing of the effects supports a weight-loss mechanism rather than a short-term life reset. "It’s the success that you have and the rapidity of that success that I think is the biggest kind of psychological shift in your brain." — Claire Barrett: Describing how losing weight changed her confidence and motivation personally.

Implications: GLP-1s may do more than reduce weight: they could alter women’s labor-market outcomes, partnerships, and spending patterns. But high costs, side effects, and possible inequality mean policy must balance health gains, discrimination concerns, and access.