In one sentence, describe what the following article is about:

Choose fruits and vegetables that offer an array of colors for the best nutrients, such as cantaloupes, carrots or tomatoes. Avoid vegetables that contain starch, such as corn. Instead, eat green vegetables like spinach, broccoli or green beans. Choose whole grain foods, rather than processed flour or foods with high sugar content. Healthy grains include barley, oats and brown rice. These foods are rated low on the glycemic index (GI), which measures the effect of carbohydrates on blood glucose levels in the body. High levels of glucose can lead to insulin resistance. Avoid salty and processed snacks like chips or pretzels.

Summary:
Eat a diet high in vegetables and fruits. Eliminate bad carbohydrates. Choose snacks with low GI levels, such as nuts, beans and dried fruit.