Image via Ted Naiman @tednaiman on Twitter
Written by Alex Parren, Nutritionist, Personal Trainer and Athlete
In recent years, many food and drink brands have been heavily promoting ‘high protein’ products while emphasising the importance of a high protein diet. But it’s important to understand the role protein actually plays in a healthy diet, what is enough versus what is too much, and the best sources. We get the expert insight from Aaron Bolton MSc, a gym-owner with a Masters in Strength & Conditioning as well as a champion weightlifter.
What does protein do to your body?
Protein is one of the three main macronutrients, which are protein, fat, and carbohydrates. These three macronutrients make up all food in varying ratios. Aaron explains that, “Protein is made up of amino acids, which serve as the major structural component of muscle tissue. Protein is an essential part of all cell membranes and plays a vital role in cell signalling.”
Enzymes are proteins required for chemical reactions to take place in the body, and some hormones such as insulin and glucagon are also protein in nature. What this means is that a lack of protein can inhibit the ability to grow, repair, and maintain body tissue.
There are 20 amino acids, 12 of which are ‘non-essential’ which means the body can synthesise them and they do not need to be consumed in the diet. However, the remaining 8 amino acids are considered ‘essential’ and need to be sourced through food and drink.
What are the best sources of protein?
The vegan movement has gained traction over recent years and there has emerged a prevalence of vegan protein - such as soya, pea protein, and even rice. As the composition of protein can vary among sources, it is important to consider the quality of each protein source to understand its nutritional benefits and impact it may have within the body. A protein can be assessed by looking at its essential amino acid composition, digestibility, and bioavailability of amino acids.
Aaron explains, “Protein is available from a variety of sources including animal and plant origins. Animal sources (eggs, milk, meat, fish and poultry) are considered complete sources of protein as they provide all of the essential amino acids. The majority of vegetable sources, such as nuts, seeds and wholegrains, lack one or more of the essential amino acids and are therefore incomplete sources of protein.”
With that said, a person wishing to meet their protein intake via plant sources can ensure a consumption of all essential amino acids by eating a large variety of vegetables, fruits, grains and legumes. Quinoa is a good choice of vegan protein as this is considered a complete protein source.
If you are looking at foods with added protein like Superzeros breakfast cereal, it may be better to look for those with whey protein than those with vegan protein. Aaron explains that, “Whey protein is a leftover by-product from the manufacturing of cheese and provides high levels of essential and branched chain amino acids, vitamins, and minerals. Whey isolate goes through a microfiltration process resulting in a higher protein and lower fat content than whey concentrate and may be a more suitable choice for those with lactose intolerance.”
How much protein should I eat?
This is the million dollar question, and as such there has been lots of research done to investigate optimal protein intake as well as how much protein the body can absorb from a single meal. One important consideration to make is nutrient timing, which refers to a strategy of spreading out your protein consumption throughout the day. Scientists still can’t quite agree on how much protein the body can successfully absorb in one meal, so it’s recommended that you don’t eat too much protein in one sitting to give the body a better chance of absorbing it and making use of it without it going to waste.
When it comes to deciding how many grams of protein to eat each day, Aaron says, “The protein requirements of strength and endurance athletes are greater than those living sedentary lifestyles. Recommendations for athletes range from 1.2-2 grams per kilogram of bodyweight per day, whilst 0.8 grams per kilogram of bodyweight per day seems to be adequate for all other healthy individuals.”
This means that an 80kg adult who spends 8 hours a day working in an office and an hour at the gym, should aim for around 64g of protein per day. If you do a lot of strength training and are actively trying to build muscle mass, you could increase this to 96-160g per day depending on your training style and goals.
Is it possible to have too much protein in your diet?
Some studies have found that a lot of adults do not eat enough protein, and one scientific review even suggests that current guidelines for protein intake are not enough, and that adults should be eating even more protein than recommended. The key takeaway here is that the average adult would not need to worry about eating too much protein. However, it’s still important to understand how much might be too much, and what problems this may cause.
Aaron says, “There is no evidence to suggest that a high protein diet has any negative outcomes in healthy individuals. However, a high protein intake may be damaging in people with pre-existing kidney disease due to the excess nitrogen found in the amino acids.”
“Furthermore, consuming high amounts of protein can result in a higher saturated fat intake depending on food choices. For example, red meat has a higher saturated fat content compared to poultry. Research by Pan et al., 2012 associated red meat consumption with an increased risk of cardiovascular disease and cancer mortality, suggesting that leaner protein choices may be better for health.”
While protein deficiency is uncommon in western society, severe protein deficiencies can lead to edema (swollen and puffy skin), fatty liver, skin, hair and nail problems. Other issues may include a loss of muscle mass, greater risk of bone fractures, stunted growth in children, and increased severity of infections. An important point to consider is that diets low in protein may also lead to greater appetite and calorie intake which can negatively impact weight loss.
The importance of a high protein breakfast
A study published in the National Library of Medicine found that high protein breakfasts may help to improve appetite control, food intake, and body composition. As protein has a high satiety effect, people are less likely to experience hunger and cravings which can help when looking to control body weight and make better food choices throughout the day.
Aaron says, “As the name ‘breakfast’ suggests, it is the breaking of the overnight fast when the body is more likely to be in a negative protein balance, so a high protein breakfast can mitigate this. Spreading the remaining protein requirement throughout the day can also help with issues of cravings and overeating”.
About the author: Alex Parren is a Freelance Health & Fitness writer as well as a qualified Personal Trainer and Nutritionist.