So what do we need protein for? Repeat after me: “growth, repair and maintenance”. How much protein do we actually need on a daily basis? A surprisingly small amount.
The average requirement for women is roughly 46 g per day with a higher amount of about 56g per day for men. This amount varies based on the level of activity and the body size.
And, if you like maths and want to know how to work it out, here’s the calculation:RELATED: RECOMMENDED PLANS FOR YOU
Body weight in kg multiplied by 0.8. For example, for a 60 kg woman, her protein requirement is 60 x 0.8 = 48g. This is the right amount of protein per day.
And, just to give you an idea of the protein content of food, most meat, poultry and fish contain around 20-25% protein. A 100g chicken breast will therefore contain 25g of protein.
It’s very easy to meet our daily requirement by eating 2 servings of protein rich foods a day. In terms of vegetable proteins such as beans and lentils, a standard serving of around 200g (or 1 cup) contains around 20g of protein, and nuts and wholegrains also contain around 5-6g of protein per 100g serving.
As you can see from this data, as long as you have a (relatively!) balanced diet you will meet your daily protein requirements effortlessly.
Should we be eating more protein rich foods?
Well, we know from a weight control perspective that protein foods are very ‘sating’, they are digested slowly and help keep us feeling full longer. A number of studies have demonstrated that higher protein diets do tend to support weight loss.
There’s also the thermic effect of proteins, protein foods use double the amount of energy to digest them compared with the other food groups. So, for example if you eat 100 calories of pure protein, at least 20 calories are used up digesting it which means you then naturally ‘consume’ fewer calories.
A win win for both appetite reduction and reducing calories!
We also know that protein is essential for muscle growth so it is an important food group for sports professionals.
Can you eat too much protein?
There is however, an upper limit for protein according to a review published by the “International Journal of Sport Nutrition and Exercise Metabolism” of about 2.5g per kilo of body weight.
So if we go back to our example of our 65kg women, according to this review she should not eat more than 162.5g of protein per day (65 x 2.5g). The issue here is that as protein foods are harder to digest, the kidneys have to work a bit harder to process and remove protein metabolites (waste products) such as urea.
A more recent review linked excessive consumption of animal protein in middle age to an increased risk of cancer. The possible reason cited by the study was linked to high protein consumption increasing levels of the growth hormone, IGF-1 which encourages cell growth.
This link was only found with animal protein, not with plant proteins, and conversely additional protein was found to be protective for health after the age of 65.
So, what is the right amount of protein per day?
In a nutshell, it is once again all about moderation. There’s no doubt that we need a sufficient amount of protein, but we certainly do not need to be consuming animal protein by the bucket load.
– Aim for 1-2 servings of protein rich foods a day and ideally 1 of these should be a vegetable protein.
– Don’t forget that seeds, nuts, eggs, dairy products and wholegrains also contribute towards your daily protein intake.
– For weight control, ensure that every meal contains at least a small amount of protein, and no, you do not need to have a steak for breakfast! Protein rich breakfasts include eggs, yoghurt and nuts.
– Be aware that your protein intake is closely related to your age and level of activity. The young and the elderly may need more protein in proportion to their weight. Very active people will also have a higher protein requirement.
Bilsborough, S and Mann, N. (2006) A Review of Issues of Dietary Protein Intake in Humans International Journal of Sport Nutrition and Exercise Metabolism, 16, pp. 129-152
Levine, Morgan E., Jorge A. Suarez, Sebastian Brandhorst, Priya Balasubramanian, Chia-Wei Cheng, Federica Madia, Luigi Fontana et al. (2014) ‘Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population’, Cell metabolism 19, 3 pp. 407-417.