Rice

Healthy carbohydrates like whole grains are part of the solution, not the problem, when it comes to diabetes. In this study, researchers analyzed 29 randomized controlled trials (the gold standard of nutrition research) to see how whole grains and ancient grains might impact health outcomes in people with diabetes. They found that brown rice significantly improved HbA1c (a measure of blood sugar control over time) and BMI (a measure of weight based on height), that oats significantly improved cholesterol, and that millet significantly improved body weight. However, given the different grains and research methods used, it was difficult for the researchers to draw broad conclusions across the whole group of grains, indicating that more research is needed to understand these effects. 
Nutr Metab Cardiovasc Dis. 2024 May;34(5):1110-1128. doi: 10.1016/j.numecd.2024.03.005. Epub 2024 Mar 7. (Magi CE et al.)

Arsenic is a naturally occurring element found in varying degrees in all soils and water, meaning that some foods, like rice, naturally contain low levels of arsenic depending on where and how it’s grown. Luckily, certain cooking and processing methods can dramatically decrease the level of arsenic rice. In this study, researchers found that parboiling your brown rice can remove up to 54% of unwanted heavy metals like arsenic from your rice (outperforming soaking or rinsing), and can also preserve important micronutrients such as zinc. You can achieve this at home by boiling your rice for 5 minutes and setting it aside for when you’re ready to cook it. You can also buy parboiled rice at the store.  
The Science of the Total Environment. 2021 Feb 10;755(Pt 2):143341. doi: 10.1016/j.scitotenv.2020.143341.(Menon M et al.)

In a large study of nearly 200,000 US adults, those eating whole grains most frequently had a 29% lower risk of developing type 2 diabetes across the approximately 30-year study period than those rarely or never eating whole grains, even after adjusting for other lifestyle factors. When looking at specific whole grain foods, common foods like whole grain breakfast cereal, oatmeal, whole grain bread, and brown rice were all linked with a lower risk of type 2 diabetes. The exception was popcorn, which was linked with a higher risk of type 2 diabetes when eaten more than once per day, perhaps due to its association with butter sauces or sugary flavorings.
BMJ. 2020 Jul 8;370:m2206. doi: 10.1136/bmj.m2206. (Hu Y et al.)