Yes, tomatoes raise blood sugar because they contain digestible carbohydrates. These carbohydrates are broken down into sugar during digestion which is then absorbed into the bloodstream contributing to blood sugar levels or blood glucose levels. But being a low-glycemic food with a GI score of only 15, the rise in blood sugar tomatoes generate is overall modest. Not to mention steady and gradual, rather than instant. This means that the limited amount of sugar obtained from eating tomatoes is absorbed at a steady rate, little by little, so the body has time to move it out of the bloodstream and into cells that process it and thus does not accumulate creating an unhealthy state of hyperglycemia.
But tomatoes are ok for diabetics only if they are consumed in reasonable amounts, according to the diabetic person’s individual nutritional requirements. An excessive intake will likely cause sugar to accumulate in the bloodstream and the diabetic body, unable to produce enough insulin to move it out (sometimes none), will become overwhelmed and suffer. Even if a food is low-glycemic and should have minimal effects on blood sugar, an excessive intake trumps the benefits of a low-glycemic index score and initiates a plethora of side effects for the diabetic patient.
Some foods like tomatoes have very little fiber (indigestible carbohydrates) to temper the rise – usually a little over 1 g of dietary fiber per 100 g of fruit. They are also extremely low in protein and fat (less than 1% protein and about 0.2% fat), two nutrients that usually help slow down digestion and the rate of sugar absorption into the bloodstream. But the good thing about them is they are about 94-95% water so also fairly low in digestible carbohydrates. This means there isn’t much to fuel the rise in blood sugar after all, hence the reason why you can actually eat tomatoes with diabetes and do so safely.
Their particular nutritional makeup is also what contributes to the low glycemic index score of tomatoes. The glycemic index (GI) is a scale estimating how foods affect blood sugar. Between 0-55 is a low GI. Between 56-69 is a moderate GI. Between 70-100 is a high GI. Tomatoes on the glycemic index hold a score of about 15, a value that applies to all varieties of the ripe fruit. This means they are a good food to consider if have diabetes or hyperglycemia. Read more in The Glycemic Index of Tomatoes.
How many carbs and sugar in a tomato?
Values assigned to different varieties of red, ripe tomatoes:
– one Roma or Italian plum at around 62 grams has 2.41 g of carbs of which 1.63 g are sugars.
– one cherry tomato at only 17 grams has 0.66 g of carbohydrates of which 0.45 g are sugars.
– one cup of cherry tomatoes weighing an estimated of 149 g has 5.8 g of carbs of which 3.92 g are sugars.
– one large fruit with an estimated weight of 182 grams provides 7.08 g of carbohydrates of which 4.79 g are sugars.
– one medium fruit weighing 123 g provides 4.78 g of carbohydrates and 3.23 g of sugars.
– one small fruit at about 91 g has 3.54 g of carbs of which 2.39 g are sugars.
Some varieties are higher in carbohydrates or sugar than others. For example:
– 100 g of red tomatoes has an average of 3.89 g of total carbs of which 2.93 g sugars.
– 100 g of green varieties has 5.1 g of carbs of which 4 g are sugars.
– 100 g of orange varieties has 3.18 g of carbs.
– 100 g of yellow varieties has 2.98 g of carbs.
Nutritional information of tomatoes courtesy of USDA.gov.
How many tomatoes can you eat with diabetes?
This is something each diabetic person has to determine for themselves. Individual intakes of certain foods are best assessed according to several factors, including current weight and state of health, level of physical activity, individual nutritional requirements, dietary restrictions. Generally, foods that are low on the glycemic index such as tomatoes (GI score: 15) can be eaten safely with diabetes, but intake is best kept reasonable.
If you are unsure of how much you can actually eat with your condition or fear certain intakes may affect your blood sugar too much, you can start off with small amounts of the likes of 1 medium tomato (estimated weight: 123 g) or 1-2 Italian plum or Roma (estimated weight per fruit: 62 g). Notice your reactions, check your blood sugar and work your way from there.
It’s important to understand that not everyone reacts the same way to the same food or the same amounts of a food, which is perfectly normal. As a diabetic, you need to adjust intakes of various foods to suit you and enjoy better control of your condition and if that means eating less of something or even avoiding some foods completely, then it’s just what you may need to do.
As for tomatoes, you can further reduce their glycemic effects with the help of these tips:
1) Small portion size. Eating less gets you less carbs per portion and lesser effects on blood sugar.
2) Not every day. If you feel they aren’t that good for you, then it might help to not eat them every single day.
3) Eat your tomatoes raw, with skin and seeds. This way, you get some fiber, albeit not much, to help with keeping blood sugar under control.
4) Never on an empty stomach or separate from other foods or with other fruits. It helps to reduce glycemic effects.
5) Pair your fruit wisely by planning your meals. Instead of just tomatoes, it’s actually better to have tomatoes with some leafy greens, chicken, fish, nuts (walnuts, pecans, almonds, cashews, peanuts), seeds (sunflower, pumpkin seeds), peanut butter, avocado, eggs or cheese. The fat and protein from these other foods will help with better blood sugar control.
6) Exercise after eating. Studies show physical exercise after eating not only helps lower blood sugar, but also improves glucose tolerance and insulin sensitivity. Not to mention it helps use up all the carbs to avoid weight gain.