There's no doubt that we're a protein-obsessed society. With fitspo and ripped bodies flooding social media, many of us worry we're not getting enough protein and supplement (expensively) in order to meet huge targets or goals.
However, while protein is an essential nutrient for overall health, we don't need as much as we might think. Protein deficiencies are rare in developed countries like Australia, and we can easily reach our recommended protein intake from our everyday diets.
"There is certainly a growing popularity of high protein diets -- you just have to look at the protein supplement industry and you will see that there is a new protein powder on the shelf every day," Robbie Clark, dietitian and sports nutritionist, told The Huffington Post Australia.
Most Australians eat far more protein than they actually need, so deficiencies are rare.
"The marketing of these products from supplement companies and some health professionals is overwhelming and can make the general public feel like they are missing out if they are not consuming a protein supplement."
On top of this, with all the attention around high protein diets such as Paleo, it can be confusing to know how much protein we really (and safely) need.
"This topic is quite controversial as there is currently no upper level of intake set for protein. The upper level of intake of a nutrient is the amount you can ingest before experiencing negative results of symptoms -- anything ranging from nausea to toxicity or poisoning," Clark said.
"Most Australians eat far more protein than they actually need, so deficiencies are rare."
Here's what you need to know about protein and excessive protein intake.
How much we need
"It's important to understand that everyone's protein needs are different and while some population groups may benefit from these supplements and high protein diets, others may not," Clark told HuffPost Australia. "Education is the key to understanding your individual protein requirements and how you can meet them."
The main factors that play a role in determining how much protein you need in your diet include weight, age, health status and level of physical activity.
As a rough guide, the recommended dietary intake for protein per day is:
- 0.75 grams of protein per kilogram of body weight for adult women (i.e. 45 grams for 60 kilogram woman)
- 0.84 grams of protein per kilogram of body weight for adult men (i.e. 67.2 grams for 80 kilogram man)
- Approximately one gram of protein per kilogram of body weight for pregnant and breastfeeding women, and for men and women over 70 years of age.
- The needs of children and adolescents also vary according to their age and weight.
"The recommended dietary intake is the amount of a nutrient you need to consume to meet your basic nutritional requirements. In a sense, it's the minimum amount you need to keep from getting sick -- not the specific amount you are supposed to eat every day," Clark said.
People who are physically active, as well those who are injured, will benefit from more protein than recommended above.
"There may be certain population groups or health conditions that require higher amounts of protein," Clark said. "For example, people who are physically active need more protein than people who are sedentary. Other instances where you might require more protein is if you have a physically demanding job, you walk a lot or do any form of exercise.
"Athletes -- in particular strength and resistance training athletes such as bodybuilders and contact and power sports athletes -- are amongst the population who require the most amount of protein (1.4-1.7 grams per kilogram of body mass), followed by endurance athletes (1.6 grams per kilogram of body mass). This is to aid in muscle recovery and building, and to meet their higher energy requirements."
Clark said elderly people also need significantly more protein to help prevent age-related health conditions and diseases such as osteoporosis and sarcopenia (reduction of muscle mass and strength).
"Finally, people who are recovering from injuries or surgery and those with chronic disease may also require more protein to help prevent further tissue damage and assist repair," Clark added.
How much is too much?
As there is currently no safe upper level of intake set for protein, it is difficult to specify how much protein is too much. However, there are general guidelines to follow to ensure you're eating appropriate amounts.
"Even though a relatively high protein intake is healthy and safe, eating obsessive amounts of protein is unnatural and may cause harm," Clark told HuffPost Australia.
"Our current dietary guidelines suggest that our recommended dietary intake of protein should make up 15-25 percent of total energy (calories) per day. It may be safe to go up to 35-40 percent, but anything beyond that is unknown and may be unsafe."
The potential risks
According to Clark, the possible short and long term risks in relation to excessive protein intake will depend on an individual's requirements, their current state of health and genetics. The potential risks for excessive protein intake are as follows.
"If you are consuming too much protein and consequently have a very low intake of carbohydrates, your body will break down muscle tissue to make glucose (your body's preferred fuel source). This causes muscle wastage, reduced metabolism and a buildup of ketones," Clark said.
"High protein diets usually lack fibre (predominantly from carbohydrates such as whole grains and legumes). Avoiding these foods leads to an overall low-fibre intake, which can result in constipation, bowel disorders and increased risk of colon cancer."
According to Clark, high protein intake (predominantly from animal products) may also be high in saturated fats and cholesterol, which is associated with a range of chronic inflammatory conditions including heart disease and type 2 diabetes.
My main concern with people who have an excessive focus on high protein foods, is that they may displace other valuable, nutrient-dense foods (such as fruit and vegetables) or other important nutrients such as carbohydrates and fibre from the diet.
"The liver and kidneys are put under strain because they have to detoxify and eliminate unusually high quantities of protein byproducts. This may not necessarily be the case in healthy individuals but kidney problems may be exacerbated in people with diabetes," Clark said.
"High protein intakes based on the consumption of large amounts of animal foods (meat and dairy foods) may result in a greater fat intake and may increase your fluid requirements.
"Greater losses of body calcium may increase the risk of osteoporosis in at-risk populations as consumption of high animal protein products cause people to excrete more calcium than normal through their kidneys."
"Excessive intake of protein tends to be expensive (and in some cases unsustainable), especially if you are using protein supplements," Clark told HuffPost Australia.
By including animal and/or plant protein in our diets, most of us will meet our protein intake without the need for expensive supplements.
"Generally speaking, animal protein provides all the essential amino acids (building blocks for protein) in the right ratio for our bodies to make full use of them."
Besides meat, other good quality animal protein sources include:
- Poultry and fish
- Dairy products such as milk, cheese, yoghurt
There are plant-based foods that also contain good sources of protein without the cholesterol and risk of carcinogens, even if they do not have the same complete amino acid profile as animal protein. Some good quality sources of protein from plant-based foods include:
- Legumes and beans (such as peas, chickpeas, kidney beans and lentils)
- Nuts, seeds and nut butters and milks
- Soy products e.g. tofu, tempeh and soy milk
- Spreads such as hummus and tahini
- Some grain and cereal based foods such as quinoa, amaranth, brown rice, whole wheat bread and pasta and oats
"My main concern with people who have an excessive focus on high protein foods is that they may displace other valuable, nutrient-dense foods (such as fruit and vegetables) or other important nutrients such as carbohydrates and fibre from the diet," Clark said.
If you are following a high protein diet, ensure you include a range of important whole foods -- whole grains, fruit, vegetables, nuts and seeds can all help keep your body functioning optimally.