See Nutrition Science's Most Preposterous Result, from The Atlantic, May 2023.

Papers:

• Choi 2005 https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/1152788

• Korat 2018 http://nrs.harvard.edu/urn-3:HUL.InstRepos:37925665

• Nutr 2019 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6821541/

Resolves to my best guess five years after creating the market. If there are multiple causes, will resolve to my subjective weighting of factors. I will not bet in this market.

• Reverse causation - If being at low risk of diabetes causes people to eat more ice cream.

• Substitution effects - If people who eat ice cream eat less of other, less healthy, desserts.

• Nutritional value - If ice cream is a healthy addition to the typical diet.

• Demographics - If ice cream consumption correlates with higher income or other demographic factors that correlate with lower diabetes risk.

• Emotional wellbeing - If ice cream increases happiness or reduces stress in a way that has health benefits.

• Slow eating - If ice cream is eaten slowly, and this has health benefits over foods that are eaten quickly.

• Not correlated - if ice cream consumption is not correlated with reduced diabetes risk, for example if studies that appear to show otherwise are due to chance.

If you have hot takes, please suggest them in comments and I may add new answers. I may also add my own hot take(s).