Tomato Carbs: Exact Count Per Serving & Nutrition Facts

A medium raw tomato (123g) contains 5.0 grams of total carbohydrates, with 1.5 grams of dietary fiber and 3.2 grams of natural sugars—making net carbs just 3.5g. This nutritional profile applies to common varieties like Roma and beefsteak when consumed fresh.

Understanding the precise carbohydrate composition of tomatoes is essential for meal planning, especially if you're managing diabetes, following a low-carb diet, or tracking macronutrients. Let's explore the science-backed details that help you make informed dietary choices.

Tomato Carbohydrate Breakdown: What's Really Inside

Tomatoes are primarily composed of water (95%), but their carbohydrate content plays a significant role in nutritional planning. According to USDA FoodData Central, the carbohydrate profile varies slightly by variety and preparation method:

Tomato Type	Total Carbs (per 100g)	Dietary Fiber	Sugars	Net Carbs
Raw, all varieties	3.9g	1.2g	2.6g	2.7g
Roma	3.6g	1.3g	2.3g	2.3g
Cherry	4.4g	1.1g	3.2g	3.3g
Canned whole	4.1g	1.1g	3.0g	3.0g
Sun-dried	24.5g	7.9g	16.6g	16.6g

This comparative analysis from the USDA's National Nutrient Database reveals how preparation methods dramatically affect carbohydrate density. Sun-dried tomatoes concentrate sugars through water removal, while canned varieties maintain similar profiles to fresh with minor processing variations. The USDA FoodData Central remains the most reliable source for standardized nutritional information.

How Tomato Carbs Fit Into Different Dietary Approaches

For keto dieters, tomatoes present an interesting case study. While technically non-starchy, their sugar content requires portion awareness. A single medium tomato contributes approximately 2% of a standard 25g daily keto carb limit. The American Diabetes Association recommends tomatoes as a non-starchy vegetable option due to their low glycemic impact (GI 15-30).

Interestingly, tomato carbohydrate composition has evolved through selective breeding. Historical varieties from the 1950s contained slightly higher sugar concentrations (3.1g per 100g) compared to modern cultivars (2.6g), according to research published in the Journal of Agricultural and Food Chemistry. This subtle shift reflects breeding priorities focused on balanced flavor profiles rather than carbohydrate reduction.

Practical Applications for Meal Planning

When incorporating tomatoes into carb-conscious meals, consider these evidence-based strategies:

• Maximize fiber benefits: Consuming tomatoes with skins intact increases fiber content by 15%, improving satiety and blood sugar management
• Pair strategically: Combine with healthy fats like olive oil to enhance lycopene absorption without significantly impacting carb totals
• Portion awareness: For strict low-carb diets, limit sun-dried tomato servings to 15g (¼ ounce) to maintain net carb counts under 4g
• Seasonal advantage: Summer-ripened tomatoes contain 12% less sugar than off-season greenhouse varieties, per University of California agricultural studies

Common Misconceptions About Tomato Carbohydrates

Many believe all tomatoes have identical carb profiles, but research shows significant variation. A 2022 analysis in Nutrition Reviews demonstrated that heirloom varieties average 0.8g more sugar per 100g than commercial hybrids. This difference becomes meaningful when consuming multiple servings daily.

The context boundary here is crucial: while tomatoes are generally low-carb friendly, certain preparations cross into moderate-carb territory. Tomato paste (72g carbs per 100g) and ketchup (27g carbs) transform this vegetable into a significant carbohydrate source through concentration and added sugars.

Maximizing Nutritional Value While Managing Carbs

For optimal blood sugar management, pair tomatoes with protein sources. A study in the American Journal of Clinical Nutrition found that combining 100g of tomatoes with 30g of lean protein reduced post-meal glucose spikes by 22% compared to tomatoes alone. This practical application demonstrates how food combinations affect the real-world impact of tomato carbohydrates.

When tracking carb intake for medical reasons, always use raw tomato measurements as your baseline. Cooking methods like roasting concentrate natural sugars through water evaporation, increasing carb density by approximately 25% per equivalent volume.

How many carbs are in a medium tomato?

A medium raw tomato (123g) contains 5.0 grams of total carbohydrates, with 1.5 grams of dietary fiber and 3.2 grams of natural sugars, resulting in 3.5 grams of net carbs.

Are tomatoes suitable for a keto diet?

Yes, tomatoes can fit within keto parameters when portion-controlled. One medium tomato provides approximately 3.5g net carbs, representing about 14% of a strict 25g daily carb limit. Cherry tomatoes have slightly higher sugar content, so Roma varieties are preferable for stricter keto protocols.

Do cooked tomatoes have more carbs than raw?

Cooking concentrates carbohydrates by removing water. Roasted tomatoes contain approximately 25% more carbs per equivalent volume than raw. Sun-dried tomatoes have significantly higher carb density (24.5g per 100g) compared to raw (3.9g), while tomato paste contains 72g carbs per 100g due to extreme water reduction.

Which tomato variety has the lowest carb content?

Roma tomatoes generally have the lowest carb content among common varieties, with 3.6g total carbs per 100g (2.3g net carbs). They contain slightly less sugar and more fiber than round beefsteak or cherry tomatoes, making them preferable for strict low-carb diets.

How do tomatoes affect blood sugar levels?

Tomatoes have a low glycemic index (15-30) and minimal impact on blood sugar due to high water content, fiber, and relatively low sugar concentration. The American Diabetes Association classifies tomatoes as a non-starchy vegetable suitable for diabetes management when consumed in standard portions (½ cup).