Tomatoes are a staple in kitchens around the world. Originally domesticated in Mesoamerica and South America, they slowly and surely spread across the globe after Spanish Colonisation. The word “tomato” comes from the Aztec word “tomatl.” Their use hasn’t changed much over the centuries as nowadays they’re found in everything from salads and sauces to soups and sandwiches; very similar to how they were eaten by Mesoamerican cultures. However, what’s unique in the modern perspective is their scientific classification; There's often confusion about whether they are fruits or vegetables. Here, we'll explore the reasons why tomatoes are considered both fruits and vegetables and explain why, from a nutritional standpoint, they are correctly called vegetables.
TL;DR: They’re both. Their classification is one science doesn’t disqualify them from being classified as something else in another.
The question involves three branches of science: Biology, botany (which is technically a sub-branch of biology), nutrition, as well as the culinary arts. It doesn’t help that biology, botany, and nutrition have the same terms, but with differentiating definitions.
How Fuit and Vegetable are defined across disciplines.
In biology “vegetable” doesn’t have a specific classification. Rather it’s a loose term used to describe edible plant parts. This includes leaves (such as lettuce, spinach), stems (like celery, asparagus), roots (carrots, beets), tubers (potatoes), bulbs (onions, garlic), and even flowers (broccoli, cauliflower). Biology, itself, doesn’t specifically define “fruit” except for the term “botanical fruit” which falls under the edible plant parts definition and is, therefore, a vegetable.
Using this definition, in the world of biology a tomato is a vegetable.
Botany, which is a subdivision of biology, doesn’t use the term vegetable. A fruit is defined as the mature ovary of a flower and contains seeds.
Tomatoes develop from the ovary of the flower and house seeds, fitting this definition perfectly. In botany, a tomato is a fruit.
In culinary arts, a vegetable is considered savoury in flavour. They are often cooked and used in many savoury side courses. Fruit is defined as being very sweet or tart. They are often consumed raw and used in desserts, jams, and beverages.
Based on this, a tomato is a vegetable. This is also why biological vegetables like figs and rhubarb are considered to be fruit.
Finally, we’ve got the nutritional definition. In the nutritional sciences fruit and vegetables are very similar. However, it’s important to note that vegetables have a much lower sugar content and a much higher fibre content than fruit. Fruit are more calorie dense than vegetables, due to the higher simple sugar content, and vegetables are typically more nutrient dense than fruit. There is a lot of crossover in the nutrients provided.
Here, tomatoes (and several other botanical fruit) fit the definition of vegetables. Honestly, when it comes to your health, this is the only definition that matters, but I’ll get there later.
Why all the confusion and arguing?
Ultimately, the confusion and the ensuing debate comes down to two things. The first is a confusion about the terminology. Many people believe that the terms fruit and vegetable are taken from botany and therefore the botanical definition should hold up. Yes, the shared terminology does breed a bit of confusion. Without getting too deep into the weeds, it’s worth pointing out that these words were around long before we had a clear understanding of any of these sciences. Culinary Arts developed thousands of years before any of the three sciences, thus it’s possible to argue that those sciences took the terms from the culinary arts. Most importantly, however, despite using the same vocabulary, botany and nutrition are two very different sciences and the terms have very distinct definitions.
When it comes to dietary guidelines, designing recipes, and pretty much anything that happens to the tomato outside of your garden the nutritional science definition is the important one.
The other is a historical Supreme Court case that highlighted the dual classification:
Nix v. Hedden (1893): This U.S. Supreme Court case ruled that tomatoes should be classified as vegetables for tariff purposes. The decision was based on the common culinary usage of tomatoes, emphasizing their role in savoury dishes.
The supreme court got it right because the case was about tomatoes grown for consumption; not biological study or ornamental plants. The ruling fits both the nutritional and culinary definition of vegetables. Still, it struck a chord with small government ideologists and to this day, you’ll hear people reference this case to claim the government changed the definition just to get more tax money. Personal beliefs on taxes aside, this is nothing more than rhetorical hyperbole and highlights the need to better understand the difference between the sciences.
In summary,
Tomatoes are botanically classified as fruits because of their function in the plant’s reproductive cycle and vegetables in nutritional contexts due to their nutritional profile. By understanding these distinctions, we can better appreciate, and more accurately measure the benefits of including tomatoes in our meals, and encourage their consumption as part of a balanced, healthy diet. It’s that latter definition that drives our dietary decisions, and that is why in on this site and in our personal consultations, I will always refer to tomatoes as vegetables.