29 Apr 2022
How much protein should a balanced diet contain per day?
The role of protein
Humans need protein for muscle development and overall good health. In fact, the word protein means “first'', from the Greek word protos. This reflects protein’s primary role in human nutrition. Protein is an essential macronutrient and we need it for muscle and tissue development along with various other roles in the body.
Athletes and bodybuilders consume higher amounts of protein compared to the average person. This is because muscle gains are a priority for them and protein plays a major role in muscle formation. However, the idea that the general population should also be consuming more protein is a misconception.
Advertisements for protein bars, powders and shakes all suggest that our protein intake from food alone isn’t enough. But is that truly the case? In reality, in developed countries, most people across all ages groups and genders are actually overconsuming protein.(1) So how much protein should a balanced diet contain per day?
How much are we consuming?
As previously stated, humans need protein for healthy muscle development and bone health. Many foods, from grains and cereals to meat, dairy, nuts, eggs and legumes, contain protein.
In the UK, the Reference Nutrient Intake (RNI) for protein for adults is 0.75g per kg of body weight per day. In other words, for a man and a woman weighing 75kg and 60kg, the RNI would be 56g/day and 45g/day respectively. RNIs are also set for children aged 0 to 10 years as well as for pregnant and breastfeeding individuals. Across all age groups in the UK, average protein intakes are higher than the recommended amounts.
The National Diet and Nutrition Survey (NDNS) found that in the UK, the largest contributor to protein intake is meat. Cereals and milk/milk products are in second place.The UK Government’s nutritional guidelines encourage the population to consume more legumes along with two servings of fish per week. Ideally you should consume one weekly portion of oily fish such as salmon, mackerel or sardines. With regards to red meat, the recommendation is to reduce your intake to a maximum of 70g per day (this includes both red and processed meats).
Moreover, protein intakes should be spread out across the day. In addition, the dietary guidelines published by the Department of Health recommend that protein intakes should not go beyond twice the recommended intake. However, there was insufficient data to establish a safe upper limit for protein intake.(2)
All protein is not created equal
The jury is still out regarding the ideal amount of protein required for optimal health. In addition, the role of high-protein diets in weight loss is still controversial. There are encouraging results in the short-term and little research available for the long-term effects of such diets.
However, not all protein is the same and we should consider the differences when thinking about our protein intake. In fact, many people believe that eating more protein means eating more meat. If you eat meat, along with dairy and eggs, these provide high-quality protein. However the same is true for many plant-sources of protein. In fact, whole grains, legumes, nuts and vegetables are all great sources of protein.
Moreover, we should consider protein as a macronutrient within a food as opposed to a nutrient in isolation. In fact, the other nutrients that you consume with the protein can be just as important as the protein itself. For example, you should primarily consume protein sources that are lower in saturated fats and highly refined carbohydrates. Moreover, it can be beneficial to consume protein sources that are also high in vitamins, minerals and fibre.
In addition, if you wish to increase your protein intake without gaining weight, you should cut back on other foods to maintain the same energy intake. The foods you choose to eat more of or cut back on can affect your health positively or negatively. For example, deciding to eat more plant-based protein sources instead of highly refined carbohydrates like white bread can benefit your health.
Protein and weight loss
Kathy McManus is the director of the Department of Nutrition at Brigham and Women’s Hospital, a Harvard-affiliated hospital. When it comes to protein intake, she suggests being picky about which types of protein you want to eat more of. In fact, she discourages her patients from increasing red meat let alone processed meat in order to boost their protein intake. Instead, if you are willing to integrate more fish into your diet, McManus supports the idea stating that it may be beneficial to your overall health.
In addition, many patients ask her if a high-protein diet is the secret to weight loss. Unsurprisingly her take on the matter is that you can’t expect a miracle solution just by adding one type of macronutrient to your diet. While trying a high-protein diet in the short-term can help some people achieve weight loss, the jury is still out on this topic. In fact, the evidence is still controversial. Some scientists swear by high protein diets for weight loss whereas others tout the benefits of more macronutrient balanced diets such as the mediterranean diet.(3)
