Calorie density: that’s why nutritionists love vegetables so much

“Eat vegetables!”, “Don’t forget to include vegetables in your diet!”, “Go veggie!”… We hear these inspiring slogans almost 24/7. Every Insta-nutritionist or wellness blogger thinks that these mesmerizing phrases make them look professional in the eyes of their audience (no surprise there, they do). But, to be honest, do the reasons to include vegetables in your nutrition plan look obvious enough? Let’s find out what they can offer us in terms of health promotion and weight control!

In this series of articles, we’ll be discovering the real benefits of vegetables. And this time, we’ll find out, why do nutritionists advise to eat more vegetables? The answer is calorie density.

Check out the previous article of “The real benefits of vegetables” series:

Calorie density varies from product to product. Photo.

Benefits of vegetables: calorie density

We meet calories in every piece of food (and even things, which are not edible). Simply put, a calorie is a measurement unit of energy, which we can get out of our food while digesting it. Some food contains fewer calories per portion, while other can contain extensive quantities of energy inside while having the same portion size. In other words, they have varied calorie density. 

Calorie density is a measure of the calorie content of food in relation to its weight or volume

Let’s see, what does it mean actually. For example, we have two cups: one is filled with potato chips and the other – with cherry tomatoes. While the tomato cup contains approximately 30 kcal per portion, the chips cup carries a whole 140 kcal with the same portion size! But what conditions make these two cups so different in terms of calorie density? The answer is hidden in the contents of the considered food.

Calorie density depends on nutrients in a product's contents. Photo.

1. Nutrients

We know 3 types of nutrients: proteins, fats, and carbohydrates. Each one of them has various calorie density per 1 g. While 1 g of proteins and 1 g of carbohydrates give us 4 kcal of energy, 1 g of fats goes further and releases almost 9 kcal.

In the context of the Thermic Effect of Food, your body needs to spend some energy to digest proteins and carbs, but it doesn’t apply as much to fats. The body doesn’t need to spend much energy to “arrogate” fats to itself (as building bricks for the cells or as a part of “love handles” – it depends). Perhaps, this peculiar quality of fats was the reason for some scientists to recommend to lower fat intake to avoid obesity (but this is a highly debatable question in modern dietology). Going back to our tomato and chips cups, we can sort through the nutrients of the contents of each cup.

Nutrient comparison between chips and tomatoes. Photo.

Potato chips and tomatoes: comparison

Let’s start with potato chips. Their primary ingredient is potato, containing 77 kcal per 100 g (3.5 oz) and mostly consisting of carbs. Despite the fact, that potato chips are obviously made of vegetables, they also contain a lot of fats. Deep frying in oils literally saturates potato slices with fats, and this procedure makes them so irresistible and so dangerous for the waistline.

It the end, when potato chips are packaged and delivered to a supermarket shelf, modest 77 kcal per 100 g morph into striking 570 kcal

And the primary reason for this amazing transformation is the enormous quality of fats inside. 

Meanwhile, the tomato cup looks almost innocent. Cherry tomatoes carry only 18 kcal and almost all of them are provided by carbohydrates. If to consider the fact, that the body still needs to spend some energy to digest carbs, we can get even fewer calories. But this is not the only reason, why the tomatoes cup wins in the calorie density competition. Another secret is hidden in their liquid contents. 

Calorie density depends on quantity of water in a product. Photo.

2. Water

Water is a pure miracle. Every living creature’s body contains a lot of water. Water is an integral prerequisite for the existence of other forms of life in the universe. For dietology, water means a lot. Water participates in almost every single process, happening in the organism. Moreover, water can control appetite and even prevent overeating for some people. This is possible because water creates volume, while contains no calories at all. The miracle, no more, no less!

Potato chips and tomatoes: comparison

As well as other vegetables, raw potato contains water. But the potato loses all the water during its transformation into potato chips. This is the reason, why the chips feel so “light” – there is no water. Not a single drop. It affects the final weight of the product – if the weight of the product (in our case – potato) becomes lower, it entails higher quantity of calories. Hence, it causes the rise in calorie density. 

Meanwhile, tomatoes have great quantity of water inside – almost 94% of each tomato is water. This is what gives the tomato cup superiority. By eating only one cup of cherry tomatoes, you can literally feel full. You don’t feel that tomatoes are light or have so few calories (but they definitely do). 

Make an experiment

If you’re a scientist by nature, just try to make an edible experiment. All you need is a notepad and a pen (or any other device of your choice), a timer, and our two cups with chips and tomatoes. Decide, which one you would like to eat first and enjoy your snack. After 5 minutes, write down, how satisfactory it was in terms of satiety. Then turn on the timer and wait until you want to eat again. After that, repeat the same with the second cup and compare the results. For most people, the cup of tomatoes wins the competition. And this is the achievement of water, hidden in the tomatoes’ contents. But it is not the end of our research of calorie density.

We still have the last secret ingredient, that distinguishes low-calorie density products from high-density ones. And this ingredient is dietary fiber. 

Vegetables are rich on fiber and low on calories. Photo.

3. Dietary fiber

Basically speaking, dietary fiber belongs to the group of carbohydrates. But it acts differently when it comes to digestion. On average, dietary fiber contains about 2 kcal per 1 g for soluble fiber (which can be digested just partially) and 0 kcal for insoluble fiber (this one can’t be digested at all). Besides its modest calorie density, dietary fiber can slow down digestion and absorption of other nutrients and increase in volume. These two features of the fiber can make you feel full for a longer time – you gradually get your energy, while still feeling satisfied.  

Potato chips and tomatoes: comparison

Surprisingly, but in that regard, potato chips win the competition. 100 g of potato chips contain 3,5 g of dietary fiber, while tomatoes give only 1,2 g. Unfortunately, this advantage can’t cover all the previously mentioned drawbacks. High in fat and very poor on water, potato chips still have a very high-calorie density. Which means, that you will be craving for more and more until satisfied. It will entail higher calorie consumption and increased weight as a consequence. 

Calorie density of vegetables. Photo.

Calorie density: the sum total

A calorie density of any product is formed by three points: quality and quantity of nutrients, quantity of water, and quantity of dietary fiber in product’s contents. All the points, merged together, give us a number of calories per 100 g of a product. 

The main idea of calorie density rate is simple: if a product contains few calories per 100 g, it can be considered as a low-calorie density product. And vegetables are champions here: even so debatable potato, when boiled or baked properly, can earn this title. 

Mix low-calorie density products with high-ones. Photo.

How to use knowledge about calorie density

How can you use this knowledge to control weight? Just fill half of your plate with vegetables: they’re full of fiber and water and primarily contain carbohydrates in low quantity.

Thanks to the volume and calorie quantity ratio, they will make you satisfied for a long time

By the way, this method of food swap is handier in comparison with calorie counting – you don’t need to count calories, because you consume heavy calorie-loaded foods moderately. If you swap one cup of mac’n’cheese for a cup of steamed broccoli, you can save about 200-300 calories. In addition, broccoli is less “attractive” to our brain in terms of fat and sugar content. Hence, you will definitely consume significantly fewer calories. Of course, mac’n’cheese deserves to be integrated into your diet plan if you love them. But rather as a treat than as a regular addition to your food intake.

Another way to make your dinner richer in quantity, but lower in calorie density, is mixing. Do you love spaghetti? No need to turn your back on the favorite dish – just mix the spaghetti with vegetables, for example, zucchini. You can even make zoodles out of zucchini – just grate your vegetables with Asian-style grater or use a special spiral grater to make your zucchini look like pasta! Mix them together and get all the taste and texture benefits of spaghetti, mixed with the low-calorie density of zucchini.

Experiment more, mix your high-calorie density favorites with vegetables and discover the whole world of possibilities to control your weight and support a healthy lifestyle!

In the next article of the series “The real benefits of vegetables” we will discuss vitamins, contained in vegetables. Stay tuned!

Check out the previous article of “The real benefits of vegetables” series:

Calorie density: that's why nutritionists love vegetables so much - The Filgrate


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