Rice

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.)

Millet is a whole grain that has a rich history throughout India. However, in recent times, millet has been displaced by refined grains like white rice. In this study, researchers introduced millet-based lunches at 2 schools in Karnataka, India, and then compared the health outcomes of those 136 students to 102 students at 2 schools who ate their regular fortified rice-based lunches for 3 months. Those in the millet group significantly improved stunting (an important measure of growth and development) and BMI, while the rice group did not. Additionally, all of the millet meals had high acceptability, with the most popular ones being finger millet ildi (a steam cooked fermented savory cake), little and pearl millet bisi belle bath (a millet-lentil hot meal), and upma (a pearl and little millet-vegetable meal).
Nutrients. 2019 Sep 3;11(9). pii: E2077. doi: 10.3390/nu11092077.(Anitha S et al.)