Eating is first and foremost a celebration. What’s more enjoyable than looking forward to your dinner all day long, preferably in the company of loved ones and friends? Food is also a celebration for our bodies, which, thanks to our nutrition, get everything they need to function. For years now, science agrees that there’s a direct link between your eating pattern and your health. However, new studies and diets that flagrantly contradict each other surface every day. Besides the climate issue, we also value the importance of a healthy diet. Therefore, we decided to take a closer look at the most important nutrients, better known as macronutrients, in the coming weeks. Let’s start with proteins.
Proteins consist of long chains of amino acids. The proteins that we take in through our food are broken down into amino acids in the gastrointestinal tract, so that they can be absorbed by the body. There are about 20 types, most of which our bodies can produce themselves. However, there are 9 types that we can only obtain through our diet. They are called the ‘essential amino acids’. Most animal sources contain all the essential amino acids, but this doesn’t mean that you can only absorb them by eating meat or diary. Since animal products contain large amounts of saturated fatty acids, it’s recommended to combine them with plant-based protein sources. Even if you prefer not to eat meat or other animal products at all, there is no reason to worry. By varying your diet, you can easily get all the essential amino acids you need. Studies show that animal products are still the main source of protein intake in our Western diet. Legumes (such as chickpeas, lentils, brown or white beans) and plant-based alternatives such as tofu put less of a burden on the climate than most animal protein sources, which is another good reason to shift our protein intake more towards plant-based sources. Further on in this blogpost we will give you some clues on where to find them, but first a little more theory...
Proteins are one of the 3 macronutrients (alongside carbohydrates and fats). Proteins, carbohydrates and fats provide energy, and are therefore essential for our bodies. To function optimally, they are best ingested in a certain proportion of the total energy requirement (En%). For proteins this is between 10-15% of the daily energy intake, with a maximum recommended amount of 25 En%. In the illustration below, you can see how much energy each macronutrient provides per gram, expressed in calories.
Although proteins contain 4 kcal per gram, providing energy is not their most important feature. Proteins are mainly needed as building bocks for our cells: they ensure a good metabolism, the transport of substances through our body, the maintenance and recovery of our body tissue and are necessary for the production of blood cells, enzymes and hormones. Moreover, they play an important role in the construction and functioning of our DNA. Adequate protein intake -in combination with exercise- ensures that you can build and maintain muscle mass. Proteins and calcium are important elements for the development of a good bone structure. Finally, our body can also convert the excess protein into energy (sugar, glucose and fat).
Protein deficiency can lead to an increased risk of fractures, breakdown of muscle tissue, and a decreased resistance to infectious diseases. However, it is important to note that protein deficiency is very rare in our Western diet. An excess of protein can cause kidney problems by increasing the body's acid load. Our metabolism will then absorb calcium from our bones to neutralize the acidification, which also causes our skeleton to become more fragile.
So how much protein do we need? The answer to this question depends on a number of things: your age, your gender and your activity level. Children and the elderly need more protein, as do pregnant and lactating women as well as people who exercise intensively (strength and endurance sports). In general, an amount of approx. 0.8 grams per kg of body weight is recommended. For an adult (18 - 59 years) of 70 kilograms, this amounts to 56 grams of protein per day.
The downside of such recommendations is that they are not so easy to translate into concrete nutrition. Obviously, you would rather not spend several hours a day reading labels to see how many grams of protein a product contains, let alone calculating how many calories you eat per day and what percentage of those calories should be proteins. Fortunately, that is not really necessary: the most recent food consumption survey (2014-2015) revealed that almost all Belgians have a protein intake that exceeds the average requirement. Only 0.7% of Belgians have a shortage. So although we are bombarded by advertisements for protein diets and whey-shakes, there is no reason for concern. We Belgians (and by extension all developed countries) consume a lot of animal products. Moreover, more products than we initially realize contain protein.
To give you a clue, we list below what our 70-kg adult would need to eat to hit his recommended intake of 56 grams of protein. We provide both an example for an omnivore, a vegetarian and someone with a vegan eating pattern.
As you can see, you don't have to consume excessive amounts of food to meet the recommended intake. The table also shows that people who eat animal products - and especially meat - will fairly quickly exceed this daily recommended amount. This is not necessarily problematic, since up to the 25 En% limit there are no increased risks of kidney failure or other conditions. However, from the moment you exceed the limit of 15 En%, your body will break down and excrete the proteins, or convert them into sugar, glucose and fat. Not a direct danger, but nevertheless taxing on your body.
Vegetarians and vegans are slightly less likely to consume too much protein, but (although this is a common misconception) within a varied diet, a shortage will not easily occur. Only if you exercise intensively for more than an hour a day (or if you are pregnant, breastfeeding or have a condition that increases your protein needs), it may be recommendable to check with your doctor or nutritionist whether you need to take additional steps to reach your intake. For example, if our adult from the example above exercised intensively for an hour a day, her/his protein requirement would hover around 1.5 to 2g per kg of body weight. In this situation, a protein shake may be worth considering, as it allows you to consume large amounts of protein without having to consume large amounts of food.
To conclude, we'd like to list some protein sources for you:
Animal based
All types of meat, poultry, fish, seafood, eggs, rabbit, dairy products (milk, cheese, yogurt, sour cream, ice cream, cream, ...)
Plant based
Legumes, grain products (wheat, oats, rice, millet, quinoa, bulgur, ...), soy milk and yogurt (almond milk, rice milk, coconut yogurt etc hardly contain any protein!), soy-based meat substitutes (tofu, tempeh), nuts, seeds & kernels, green vegetables.
In the next blogpost you will read whether carbs are really the enemy, or rather a good friend... Stay tuned!
References
De Meyer, L. (2019), Moet er nog vlees zijn? p. 86 – 91. Borgerhoff & Lamberigts
Nubel, De Belgische Voedingsmiddelentabel (editie 2019)
De Ridder, K. (2016), Eiwitten, https://fcs.wiv-isp.be/nl/Gedeelde%20%20documenten/NEDERLANDS/Rapport%204/3_proteine_NL_finaal.pdf
Vlaams Instituut Gezond Leven, Eiwitten, https://www.gezondleven.be/themas/voeding/focus-op-voeding-niet-voedingsstoffen/voedingsstoffen/eiwitten