Study Links Weight Stigma and Inflammation Part 2 - Results

The Acute Inflammatory Effects of Weight Stigma: An Experimental Pilot Study

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In Part 1 we looked into the authors and methodology of the study The Acute Inflammatory Effects of Weight Stigma: An Experimental Pilot Study which was published in August, 2025. In part 2 we’ll look at the results.

Summary

Participants were divided into a weight stigma group and a control group and asked to read a one-page article and then prepare and deliver a 3-minute speech about the article. One of the articles was created to induce weight stigma, the other was not. Of the three inflammatory markers tested via blood draws during the exercise, two showed a small (non-statistically significant) increase in the weight stigma group. This is a pilot study and it is not intended to create generalizable findings, but it does show that this is worth more research and that this protocol is an option for that research. It also adds to the existing body of research that shows that weight stigma may be independently creating health issues that get blamed on being higher weight.

Deeper Dive

How was weight stigma created?

They randomized the participants to one of two groups. Each group had to read a one-page article and then create and deliver a three minute speech to camera and in front of a research assistant using “specific prompts (e.g., discuss the facts conveyed in the article, discuss the rationale driving the proposed social policy).” They were told that “the speech would be immediately evaluated by a research assistant and later evaluated by the principal investigator.”

One group was given an article that was “previously developed to induce weight stigma titled “Lose Weight or Lose Your Job” (Major et al., 2014).” The other group were given an article called “Electronics Recycling Best Practices.”

How was inflammation measured?

The test measured serum cytokines “(i.e., interleukin; IL-6, tumor necrosis factor; TNF-α, interferon; IFN-γ)” via repeated blood draws with a peripheral intravenous catheter (PIVC) this is commonly known as an IV typically placed in the lower arm or back of the hand, “at pre-task and 30, 60, and 90-minutes post-task.” During the post-task period the subjects watched a “neutral video (i.e., three 30-minute segments of a television series that presents behind-the-scenes details of how everyday items are manufactured) without reference to weight or body-relevant stimuli” between blood draws.

Finally, body measurements were taken per the study protocol and each participant was debriefed including “knowledge that the speech task was not recorded nor evaluated, explicit communication that the research team does not endorse weight bias such as the attitudes that were communicated in study materials, and the opportunity to process any adverse emotional reactions participants may have experienced due to weight stigma exposure. Participants were then compensated $60 USD and the visit was concluded.”

The tests were then processed using “commercially available kits.”

Demographics:

The study included 44 cis-women with an average age of 32.3 years (±9.4 years,) 68% were non-Hispanic white \cis women, 6.8% were American Indian/ Alaska Native, 4.5% were Asian, 6.8% were white-Hispanic, 12.6% were multi-racial (these were the only categories).

Inflammatory Markers Following Speech Tasks

Across the full sample, IL-6 increased pre- to post-task consistent with a small effect size (d=.30, p=.047; Figure 1A), as did TNF-α (d=.28, p=.070; Figure 1B). No meaningful effects were observed for IFN-γ pre- to post-task in the full sample (Figure 1C). Within the control group, IL-6 increased and displayed a medium effect (d=.62, p=.004; Figure 1D). Pre/post changes TNF-α and IFN-γ did not meet criteria for small effects in control (Figure 1E/F). Within the weight stigma group, the pre/post-task increases in IL-6 (d=.20, p=.365; Figure 1G), TNF-α (d=.43, p=.047; Figure 1H), and IFN-γ (p=.078, d=.48; Figure 1I) were all consistent with small effects. See Table S3 for details.

In the discuss section they explain:

“As for patterns of effects, no statistically significant effects were found between groups. However, the weight stigma group displayed small-or-greater effect sizes for pre-to-post change in all outcomes; the control group only displayed ≥small effect sizes for IL-6. When analyzing between-groups differences, small effects for IFN-γ and TNF-α were observed, consistent with a greater increase in inflammation in the weight stigma group than control.”

What they found here is that members of both the stigma and control group experienced effects on the studied inflammatory markers. (This makes sense to me just given the number of people who come up to me after talks I give to tell me that they can’t believe I do this for a living! Outside of my anecdata, there are also actual data showing that people experience stress about public speaking which may drive inflammation.)

When breaking the findings down between the control and the stigma groups, they found that there was a small (not statistically significant) differences in two of the three markers (IFN-γ and TNF-α) for the weight stigma group which means a slightly greater increase in inflammation in the weight stigma group. (If you want to brush up on statistical significance, head here!)

They summarize their results by saying:

Together, these results support continued investigation of weight stigma and acute physiological responses, such as inflammation…Overall, this pilot study established feasibility of an in-lab weight stigma stress task with repeated blood draws and generated preliminary effect sizes to inform future work. The observed pattern of effect sizes supports the need for larger-scale studies on the acute stress and inflammatory impact of weight stigma.

Again, this is a pilot study and it shouldn’t be expected to make strong, generalizable findings and they are clear about that. They are also clear that this is worth more research and I absolutely agree. The study adds to the literature that suggests that weight stigma creates harm (including harm that is likely to be blamed on weight, rather than weight stigma) and I’m grateful to these researchers for pointing this out.

We should remember that weight stigma is, in fact, a modifiable risk factor and we could focus on creating a world where people of all sizes can live and thrive, rather than pretending that a “solution” to weight stigma is to hope for/try to create a world where fat* people don’t exist.

This month’s online workshop is Weight-Neutral Reproductive Care with Dr. Anna Whelan, MD FACOG. There is a pay-what-you-can-afford option and all registrants get a video. Details and Registration are here!

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*Note on language: I use “fat” as a neutral descriptor as used by the fat activist community, I use “ob*se” and “overw*ight” to acknowledge that these are terms that were created to medicalize and pathologize fat bodies, with roots in racism and specifically anti-Blackness. Please read Sabrina Strings’ Fearing the Black Body – the Racial Origins of Fat Phobia and Da’Shaun Harrison’s Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this.