Tomatoes add a splash of color, bright flavor and juicy texture to sandwiches and salads, but they won't lead to the unhealthy side effects you'll commonly experience upon eating foods that rank high on the glycemic index. Although eating tomatoes causes an increase in your blood sugar, the result is only minimal.
Low on the Glycemic Index
The glycemic index assigns a number to foods that are rich in carbohydrates. This number dictates how quickly the food will cause a change in your blood sugar. Tomatoes have a glycemic index of 30, which gives them a low glycemic index. Foods with a glycemic index of 55 or lower are considered low, meaning that while they'll raise your blood sugar, the increase you experience will be slow and steady. High-glycemic foods have an index of at least 70 and cause your blood sugar to spike rapidly.
Other Tomato-Based Products
Other tomato-based products cause a slightly quicker increase in your blood sugar than plain tomatoes. Tomato juice, for example, has a glycemic index of 35, as does tomato sauce with no added sugar. Tomato sauce with added sugar has a glycemic index of 45. Although these numbers are higher than plain tomatoes, they still fall within the low-glycemic range, making them safe to eat without causing a major change in your blood sugar.
Focus on Low-Glycemic Foods
When developing your diet, choose tomatoes and other low-glycemic foods such as sweet potatoes, legumes, apples and unsweetened yogurts. Stay away from high-glycemic foods such as white bread, crackers and sources of refined sugar. Repeatedly eating foods with a high glycemic index causes your blood sugar to fall shortly after it spikes. When it falls, you'll often crave additional foods and can overeat. This cycle can eventually lead to obesity and weight-related medical issues such as diabetes.
Source of Nutrients
In addition to their low-glycemic properties, tomatoes are also a valuable source of nutrients. One cup of raw, chopped tomatoes provides 64 percent of the daily recommendation of vitamin A for women and 50 percent for men. Vitamin A contributes to several important functions in your body, including healthy skin, teeth and bones. The vitamin also promotes good vision. One cup of tomatoes provides about 33 percent of the daily recommendation of vitamin C for women and about 27 percent for men. This vitamin strengthens your immune system, too.