The combination of foods will cause a slower rise to blood sugar. Think of the colors blue and red. When you use each color separately, you get 2 distinct colors. When you combine them, the overall effect is purple. The same is true with food.
Different foods turn to sugar at different rates.
For example, blood sugar will increase faster and higher after eating jelly beans than it would an equal caloric amount of brown rice. When planning meals, individuals should choose foods which turn to glucose more slowly. It's also beneficial to choose food from each food group at each meal. Foods which are absorbed slowly will help slow the digestion of foods normally absorbed quickly. When eaten together, the protein and fat in the chicken slows the absorption of the sugar in the orange.