First, a distinction must be made between whole grains and their refined counterparts. Whole grains, such as oats and whole wheat, offer loads of nutrients and a lowered risk of disease. But highly processed grains are stripped of fiber and nutrients. Although these refined grains may be easier to digest, they spike blood sugar levels, which can cause food cravings that lead to overeating, weight gain and obesity.

Nevertheless, gluten in grains, such as wheat, rye, spelt, barley and oats (under specific circumstances), is unhealthy for people who can’t tolerate this protein, including those with celiac disease, a serious autoimmune disorder. In addition, the substance causes gastrointestinal distress in individuals with gluten sensitivity.

Folks who must restrict carbohydrates in their diet—for example, people living with diabetes—also need to be selective about the amount and kinds of grains they eat, as some foods are better for them than others.

Experts advise people to use a commonsense approach: Monitor your response to eating grains because how healthy these foods are depends on their effect on you.