Many of us consciously eat high-protein foods, with protein-rich products available, but how much protein do we really need? And does it really help us lose weight?
At the beginning of the 20th century, the Arctic explorer Vilhjalmur Stefansson spent five years collectively eating only meat. This means that the diet consists of about 80% fat and 20% protein. Twenty years later, he did the same thing as part of a year-long experiment at Bellevue City Hospital of New York in 1928.
Stefansson wants to refute those who argue that humans can not survive if they only eat meat. But unfortunately for him, in both settings he quickly became ill while eating lean meats. He developed "protein poisoning", dubbed "rabbit hunger". Symptoms disappear after he lowers his protein intake and he increases his fat intake. In fact, after returning to New York City and to a typical US diet with a more normal level of protein. She reportedly found her health deteriorating and returned to a low-carbohydrate, high-fat, and high-protein diet until her 83-year-old death.
Initial experiments are some of the few cases recorded from high protein intake that have extreme side effects - but even though the sale of protein supplements is soaring, many of us are still unsure how much protein we need, how best to consume it, and if too much, or too little, is dangerous.
Although obesity rates have doubled over the past two decades, we have become increasingly aware of what we eat. In recent years many of us have swapped white bread for brown and wheat bread and full fat milk for skim. Taking center stage in our healthy kicks is protein, with protein balls, sticks and an enhanced protein version of staple products, from cereals to soups, dominant supermarket shelves. And with a global protein supplement market worth $ 12.4bn (£ 9.2bn) by 2016, it's obvious we're buying into the idea that we need as much protein as possible.
But some experts now argue that food with exhaled protein (and price) is a waste of money.
Brand supplements suggest drinking protein shakes after exercise to help growth and repair muscle tissue
Proteins are essential for the body to grow and improve. Protein-rich foods such as milk, meat, eggs, fish and beans are broken down into amino acids in the abdomen and absorbed in the small intestine, then the liver gets the amino acids the body needs. The rest is doused in our urine.
Inactive adults are advised to eat about 0.75g of protein per day for each kilogram of weight. On average, this is 55g for men and 45g for women - or two servings the size of meat, fish, tofu, beans or nuts.
Not getting enough protein can cause hair loss, acne prone skin and weight loss as muscle mass decreases. But these side effects are very rare, and most only occur in those with eating disorders.
However, most of us have proteins associated with muscle building. This is accurate. Strength-based exercise causes protein breakdown in muscles. In order for muscles to grow stronger, proteins need to rebuild. A type of amino acid called leucine plays a very big role in triggering protein synthesis.
Some experts even argue that not consuming post-sports protein can cause muscle damage to be higher than synthesis - meaning there is no net gain in muscle mass. Supplements suggest taking protein shakes after exercise to help the growth and repair of muscle tissue, usually in the form of leucine-rich whey proteins, a by-product of cheese making.
Many people eat sports nutrition products such as protein bars and shakes
Many consumers agree. Research firm Mintel's 2017 Report found that 27% of British people use sports nutrition products such as protein bars and shakes. This figure rose to 39% for those who exercise more than once a week. But more than half of individuals who use the product (63%) find it difficult to say whether they have any effect.
Protein bars are actually just candy with a little extra protein
Indeed, research on the strength of muscle protein supplementation varies. A 2014 analysis of 36 papers found that protein supplementation had no impact on lean mass and muscle strength during the first few weeks of endurance training in untrained individuals.
Over time and when training gets tougher, supplements can increase muscle growth. However, this paper also concludes that this change has not been proven in the long run. The 2012 review paper further says that protein "improves physical performance, recovery training and lean body mass" ... but for the benefits of being optimal, it should be combined with fast acting carbohydrates.
But even if athletes and sports audiences can benefit from a post-exercise protein boost, that does not mean they should grab supplements and smoothies. Most people get more than their daily recommendations from food, says Kevin Tipton, a sports professor from Stirling University. "No one needs supplements. They are an easy way to get protein, but there are no supplements you can not get in food. Protein bars are really just candy with a little extra protein. "
The global protein supplement market is worth $ 12.4bn (£ 9.2bn) by 2016
Tipton added that even among bodybuilders, products like whey protein are not as important as they want to be. "Too much focus on which supplements to take, not in the gym and work harder. There are so many other variables, such as sleep, stress, and diet, "he said.
We need to maintain our muscle mass as we age, because we become less active and weak
Most experts agree with Tipton that protein is best consumed in foods rather than supplements. But there are some exceptions, such as difficult athletes reaching their daily protein targets, showing Graeme Close, professor of human physiology at Liverpool John Moores University. "I believe most require more than the recommended daily allowance, and there is good evidence to support this," he said. In this case, he says, wobble can be useful.
Which other demographic can benefit from extra protein? Parents. That's because as we get older, we need more protein to maintain muscle mass. But we also tend to eat less protein as we get older because our tastes start liking sweet rather than savory.
Emma Stevenson, professor of sports and exercise science at the University of Newcastle, works with food companies to get more protein into snacks known to the elderly to be purchased on a regular basis, such as biscuits. "We need to maintain our muscle mass as we get older, because we become less active and weak," he said.
Close says parents should increase protein intake to about 1.2g per kg body weight.
Most people get more than their daily recommendations of protein from their diet
Fortunately, it's hard to have too much protein. While we have the upper limit of protein intake, it's "almost impossible" to reach, Tipton said. "There are concerns among some dietitians that a high protein diet can hurt the kidneys and bones, but evidence in healthy people is minimal. There may be problems if a person with kidney [problem] eats large amounts of protein, but the likelihood of side effects is very low. "
If you are trying to lose weight, it is more important to have a high protein breakfast
But while the protein itself is harmless, many high-protein carbohydrate supplements are called FODMAPs that trigger digestive symptoms such as bloating, gas and abdominal pain. Stevenson suggested reading the labels carefully on supplements, bars, and balls. "Often, they are very high in calories and contain lots of carbohydrates, often in the form of sugar. You do not have to think about it because it says it's a healthy high protein, "he said.
Weight loss
Proteins have long been associated with weight loss, with low-carbohydrate, high-protein diets such as Paleo and Atkins that promise to extend a feeling of satiety. People fail to lose weight often because they feel hungry, and MRI research shows that a high protein breakfast can help stop hunger in the future.
There is sufficient evidence that the protein fills, says Alex Johnstone of the University of Aberdeen. If you are trying to lose weight, then it is more important to have a high-protein breakfast, such as beans on toast or a milk smoothie, rather than having a supplement.
But he does not advocate the "Atkins-type" diet and has found that carbohydrate trimming adversely affects intestinal health (and we now know that maintaining a healthy bowel is essential for many aspects of our health and well-being).
Protein is often high in calories and can contain many carbohydrates
In contrast, Johnstone recommends that overweight people eat a high-protein and moderate-carbohydrate diet, which consists of 30% protein, 40% carbohydrate and 30% fat - compared with an average diet of about 15% protein, 55% carbohydrates and 35% fat.
However, of course, increasing protein intake alone will not help you lose weight. Choosing lean meats like chicken or fish is the key. Studies have also shown that eating large amounts of animal protein associated with weight gain and red meat is particularly associated with an increased risk of cancer and heart disease.
Consuming more protein than is needed is waste in the form of money, and it is paid to the toilet
However, there are healthy non-meat proteins like mycoprotein, vegetable protein derived from fungi. Mycoprotein like Quorn is rich in fiber and protein.
Researchers are now looking at how this unique composition (both protein and fiber) can affect satiety and insulin levels, which are associated with type 2 diabetes. One team compared the mycoprotein diet to the chicken diet and found that insulin levels in those who ate quorn achieved the same sugar control, but required less insulin to be produced by the pancreas.
The risk of consuming too much protein is small, but the greater risk may fall because overpriced products offer us more protein than we need. "Some products labeled high protein do not, and the price is quite expensive. However, consuming more protein than is needed is waste in the form of money, and it is paid to the toilet, "said Johnstone.