The article details some of the study's methodology:
"The researchers set up four different scenarios:
1. In the first scenario the actress wore a fat suit and served herself more salad than spaghetti. This scenario witnessed students serving as well as eating 43.5 per cent less salad than the fat woman.
2. In the second one when she was wearing the suit but served herself mostly the less healthier spaghetti, 31.6 percent of the participants ate more spaghetti, regardless of what she ate.
3. The actress didn’t wear the fat suit and served herself mostly salad.
4. The actress didn’t wear the fat suit and served herself mostly pasta."
From the findings:
"The observation clearly states that people tend to eat more unhealthy food and have less of the healthy one, in the presence of an overweight person regardless of what they have in their plate."
I think that this study clearly crosses the line. I honestly was nearly sure that this was a joke as I read the article because it reads like some kind of comedy sketch.
The use of a fat suit is dehumanizing and feels like an utterly unecessary element in an otherwise thoroughly bigoted study.
As you've read, the conclusions of this study (and the title of this article) posit that regardless of what a fat person - a fat woman - eats, just being in proximity to one leads to what are deemed as "bad" food choices.
The article further de-genders this finding, using the words "overweight friend" when the study seems to have only tested this behavior with a woman in and out of a fat suit.
Why this is important? We live in a fatphobia-saturated era characterized by open fat hatred and hostility. We also live in a culture that values the scientific and the empirical. This study, I believe, seeks to legitimize and codify the ostracization of fat people - and fat women particularly. This is not only fatphobic, but also sexist. Social isolation can have affects on mental health that fat women are perhaps already experiencing due to preexisting fat shaming attitudes.
Read about The Fat Suit Study on the Cornell page.