An average size red onion which equates to about 180g has some 63 to 67 calories. Choice of cooking method and ingredients added may have an impact on the calorie count of red onions.
There are nearly a dozen red onion (Allium cepa) varieties. Some examples include Flamenco Red Onions, Red Beauty Onions, Mars Red Onions and Red Wing Onions. There are also red onions with are specialty onions such as Cipollinis. The biggest red onion variety is the Mammoth Red Onion. It is commonly grown for competitions and exhibitions.
Regardless of which variety one chooses to grow and eat, each red onion has more or less the same amount of calories.
Both red onions and yellow onions have low calories. However, red onions have a lower calorie count than yellow onions. This is one of the reasons there seems to be a greater interest in red onions.
Furthermore, red onions have additional health benefits compared to their yellow companions. This is because of the anthocyanin pigment responsible for the red color.
Anthocyanin pigments are also behind the purple in purple potatoes, or the red in red cabbage. Apparently, they signal healthy options in fruits and vegetables. Well known and documented benefits of anthocyanins in plants include antidiabetic, anti-inflammatory, cancer prevention, obesity control and prevention of cardiovascular diseases among a range of other important benefits.
Source of calories in red onions
As illustrated by the graph, sources of calories in red onion are carbohydrates at about 90%, protein at 8% and fat at 2%. The biggest component of the fat is polyunsaturated fat. Saturated fat is the second biggest. Monounsaturated fat is the smallest component. Interestingly, red onions have zero cholesterol. Red onion bulbs also have a good amount of water which keeps them fresh and bulky.
In addition, the following table shows red onion calories according to each amount served.
| Serving Size | Calorie Count |
|---|---|
| 1 thin slice | 4 |
| 1 medium slice (3mm thick) | 6 |
| 1 large slice (6mm thick | 16 |
| 1 small red onion | 29 |
| 1 large red onion | 63 |
| 1 medium red onion | 46 |
Effect of cooking red onion on calories
Depending on methods used and ingredients added in the cooking, cooking does not seem to have any serious impact on calories found in red onion. The calories remain as low as they already are in raw red onion. For example, one cup of sautéed red onion has about 67 calories, 16g carbs and 1g protein.
However, things dramatically change if other calorie laden ingredients are added to the recipe. Examples are butter and other fats. 100g of butter has more than 700 calories and 100g of olive oil has over 880 calories according to the USDA.
Growing Red Onions
For growers, red onions can easily be grown in a home garden in pots or directly in the ground. Regardless of variety, onions demand plenty of sun. The growing medium should be well-draining soil with a pH between 6.0 and 6.8. The onion plants should be planted between 3cm and 5cm deep and spaced about 15 cm apart.
