Are Tomatoes Keto?

The answer is yes, tomatoes are keto friendly. Tomatoes appear in many ketogenic recipes and are recommended by many leading ketogenic dietitians. Here is why. According to USDA data, a 100 gram raw red tomato has only 3.41g in net carbohydrates and 2.1g in fibre. Fibre does not have any influence on a person’s insulin. It does not affect insulin level. This is the reason why net and not total carbs are most interesting when calculating keto carbs. Total carbs of the same size tomato inclusive of fibre would be 5.51g.

Furthermore, according to USDA data, tomatoes have 92.5g water and 0.83g protein apart from minerals such as Potassium (250mg), Calcium (11mg) and Magnesium (11.9mg). The high water content (95%) in tomatoes is favorable to a keto diet which itself stimulates high levels of water intake.

Keto Tomato, Fruit or Vegetable?

There is often confusion whether tomatoes are a fruit or a vegetable. This creates understandable trepidation in view of a handful of keto-unfriendly fruits high in sugar/carbs content. Nonetheless, the “keto tomato” is classified as a vegetable.

Botanically, tomatoes are a fruit of the genus Solanum lycopersicum. They are a legitimate fruit because technically they develop from the ovary of the flower of the tomato plant. Furthermore, the tomato has the seed of the tomato plant in it. The seed is potent enough to sexually propagate the tomato plant in perpetuity.

The idea of a tomato being a vegetable arose in 1893 through the famous Nix v. Hedden case at the United States Supreme Court. For the purposes of tariffs imposed on imported produce, it was determined by the Court that the tomato is a vegetable. For some 130 years, it has been a “fact” that tomatoes are vegetables. This understanding has been thoroughly infused in literature and public information over time.

Despite this rather controversial legal history, the tomato is botanically fruit. However, it is normal to find tomatoes grouped with vegetables in keto literature and public information.  Keto diet categorizes tomatoes as vegetables. The USDA also categorizes tomatoes under Vegetables and Vegetable Products in its food nutrition database.

Tomatoes vs Main Goals of Ketogenic Diet

The primary goal of a ketogenic diet is to keep your carbs low, get the body into ketosis and keep it there. Thus the recommended carbs intake per day under keto is between 20 and 30 grams according to Dr Eric Berg DC.

A typical keto diet food combination comprises 70%  Fat, 20% Protein,  5% Non-starchy vegetable carbs and 5% other carbs. Tomatoes fall into the 5% which offer non-starchy vegetable carbs in a keto diet. 

Tomatoes are well within the goals of a keto diet. In fact, tomatoes are used to build a well within range typical serving size of carbohydrates on the ketogenic diet. Below are two examples as developed by Dr Eric Berg DC.

Tomato Keto Serving Example 1

Item	Carbs
250g Tomatoes	7g net carbs
170g carrots	12g net carbs
136g beets	9.2 net carbs
30g sunflower seeds	3g net carbs
42g hummus	5g net carbs
56g almonds	6g net carbs
Total Net Carbs	42.2g

Tomato Keto Serving Example 2

Item	Carbs
170g carrots	12g net carbs
136b beets	9.2 net carbs
250g tomatoes	7g net carbs
2 medium avocados	8g net carbs
56g almonds	6g net carbs
100g acorn squash	8g net carbs
Total Net Carbs	50.2g

Tomatoes are even keto friendly in slow metabolism situations. Slow metabolism is a well known factor in some individuals on a keto diet. Even when carbs are reduced, these individuals may not see corresponding weight loss results. 

In such cases, a reconfigured ketogenic diet may be necessary. For example, although both tomatoes and carrots are keto-friendly vegetables, a 100g of raw carrots has a higher amount of net carbs (6.78g) than tomatoes (3.41g). This makes tomatoes keto friendly better than carrots for individuals with slow metabolism. There are obviously other vegetables on the ketogenic diet apart from tomatoes, with much lower carbs that can be used to replace carrots. Examples include spinach and lettuce.

Are Tomatoes Keto when Canned?

Many canned tomatoes are generally not ketogenic friendly. To begin with, as explained above, an average tomato has some 3.41g of carbs. Canned tomatoes are a concentrate and therefore automatically tend to have a higher carbs content.

In addition, one other reason some canned tomatoes are not suitable for a keto diet are the added ingredients. Some of these ingredients introduce sugar and carbs which builds the carb profile of the tomatoes themselves

The example below shows a nutrition panel of a canned tomato product that is marketed as containing 2 servings.

Typical values	per 100g	per 1/2can
Energy	95kj/22kcal	189 kJ/45 kcal
Fat	0.2g	0.4g
– of which saturates	0.0g	0.0g
Carbohydrate	3.4g	6.8g
– of which sugars	3.4g	6.8g
Fibre	0.9g	1.8g
Protein	1.3g	2.6g
Salt	0.13g	0.26g

In this example, a full can (of only 2 servings) will give 13.6g in carbs and 13.6g in sugar. The catch in using some canned tomatoes, such as this one, for keto diet is in the quantity of canned tomatoes consumed. Moderation becomes the key as the carbs can add up quickly. It is thus important to check the information table at the back of the product.

Are Sun-dried Tomatoes Keto?

Overall, sun-dried tomatoes are not considered friendly to the ketogenic diet. They lose 90% of their water content through the drying process leaving them tasting sweet and very high in carbs. Net carbs in sun-dried tomatoes can be as high as 18g per 100g. This is very high.

A very small serving of sundried tomatoes is known to kick people out of ketosis. Ketosis refers to a positive state in which the body is successfully burning fat for fuel without need for carbohydrates. 

For this reason, some literature and information discourages sun-dried tomato use in a ketogenic diet. However, depending on how they are made, some tomato purees are indeed suitable for use as keto tomatoes.

Sun-dried Keto Tomato Puree

Going by the label, this Italian sun-dried tomato product is one example of keto friendly purees.  It is a sun-dried tomato product with oil, herbs and spices added. The nutritional panel on the label shows that the puree has only 1.6g of carbs per 100g serving of the puree. This is well within permissible macros for keto. 

This particular puree can be found on Amazon here. Furthermore, additional details about the product are also on the company’s website.

Below is a panel with nutritional information about the product.

	per 100g
Energy	253kcal/1042kj
Fat	25.9
– of which saturates	2.1g
Carbohydrates	1.6g
– of which sugars	1.6g
Protein	1.6g
Salt	5.6g

Keto Friendly Tomato Varieties

There are thousands of tomato varieties available to grow or purchase on the open market as fresh produce. All tomato kinds, red, yellow, purple or green generally carry the same amount of carbs per 100g, for example.

All types of tomatoes are therefore keto friendly regardless of cultivar.

However, for overall health benefits, purple tomatoes go an extra mile. They have additional health benefits associated with the antioxidants they carry due to their purple pigment known as anthocyanin. In addition, yellow tomatoes are also a different type of tomato with less acid level which is beneficial to some individuals.

How to make Keto Tomato Ketchup

Keto Tomato Ketchup Recipe (Video)

In this video, a simple method of making keto-friendly tomato paste at home is demonstrated.  The outcome are tasty keto tomatoes in paste form.

Conclusion

The answer to the question Are Tomatoes Keto is an emphatic YES. Raw tomatoes harvested from the garden or precured from the local store as fresh produce are keto-friendly. Furthermore, regardless of variety, all tomatoes are indeed keto tomatoes. However, extra care is needed when dealing with processed tomatoes such as canned tomatoes. These can be concentrated or have sugar added which makes them easily exceed ketogenic dietary numbers. Whilst some canned tomatoes are keto-friendly, reference must be made to the nutritional panel on the respective products to identify ones that are not ketogenic friendly.