having enough protein eating is one of the latest crazes to hit the food and wellness sectors. An assortment of protein-rich foods are now on sale, including high-protein breakfast cereals, yogurts and even branded chocolate bars.

The most dedicated can chew beef biltong jerky or drink protein shakes between meals.

Protein is variously claimed to help us stay fit, lose weight, and strengthen our immune systems. But different sources give conflicting opinions on how much protein we should eat. So what does the science say – and why is protein so important anyway?

In some ways, protein should be less controversial than the other two major food constituents, fat And carbohydrates.

Traditional medical advice says we should avoid fats and load up on starchy foods, while Atkins and keto diet Proponents say we should do the opposite, cutting out carbs while loading up on fat.

Protein, on the other hand, is praised by almost every school of nutrition. In addition to being the main component of muscle fibers, protein molecules play a wide range of other roles in our bodies, from providing structural support to tissues like bones and skin to carrying out crucial functions. For example, antibodies, which help us fight infections, are large protein molecules, just like enzymes, which control all the chemical reactions that occur in our bodies.

Muscle maintenance

The proteins in our tissues are constantly broken down and rebuilt by the proteins in our diet, with all the protein molecules in our muscles being completely replaced every three months. That’s why it’s so important that we eat enough protein, so we don’t gradually lose muscle over time, said Professor Benjamin Wall, a nutritional physiologist at the University of Exeter.

“Even if it’s a very small amount, if you lose a little more muscle than you gain, you’ll lose muscle over a year,” he said.

This is particularly important as we age, as muscle loss contributes to people becoming more frail with age and more prone to falls – a major cause of injury and loss of independence in older adults.

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But older people are not the only ones affected. People start to become more prone to muscle loss in their 40s, Professor Wall said.

There are two main ways to prevent muscle loss: resistance exercises (like lifting weights), squats, stair climbing, and making sure you’re getting enough protein.

The key question is how much is enough? The NHS says we should eat an average of 0.75 grams of protein per kilogram of body weight per day. This equates to around 45g per day for a typical woman and 55g for a man.

These amounts may not seem too difficult to achieve: for example, half a chicken breast, considered a typical serving, contains about 29 g of protein.

Minimum versus optimal

Although very similar amounts are also listed in many other countries’ dietary guidelines, scientists question whether these numbers are accurate.

They might be an understatement in two respects. First, they represent the minimum amount of protein people need to avoid clearly measurable muscle loss. But consuming more could still help ward off slow process of muscle loss linked to aging in the long term. “There’s the minimum requirement versus the optimal requirement,” Professor Wall said.

Second, they were developed by the World Health Organization in the 1990s, based on the amount of protein needed by an average healthy adult.

They don’t take into account that older people are less able to rebuild their muscle fibers in response to dietary protein, a phenomenon known as anabolic resistance, said Dr Elizabeth Williams, a registered nutritionist at the University of Sheffield . Due to anabolic resistance, she says: “There is a school of thought that older people have higher protein needs than the general population. »

People over 60 should aim to consume between 1.0 and 1.2g per kg per day, according to a study. expert statement from the British Association of Sport and Exercise Sciences in 2022. The authors said their recommendation should also be useful for people under 60, given that anabolic resistance begins as early as the 30s.

A second set of guidelines from the same body advised athletes to aim for 1.6g per kg per day, more than double the amount recommended by the NHS, said Dr Oliver Witard, exercise metabolism and nutrition expert at King’s College London.

Still, when it comes to building muscle, the amount of exercise people do is more important than their protein intake, Dr. Witard said. “Some people think, ‘I have a very high protein intake, I can gain muscle even if I only exercise a little.’ But the main strategy is exercise.

And there’s no evidence that eating extremely high amounts of protein, more than 1.6g per kg per day, helps people build even more muscle, he said.

People who aren’t professional bodybuilders probably don’t want to think about their protein intake in terms of grams per kilogram, Dr. Williams said. For most people, a helpful tip is to simply try to eat protein with every meal, which can be as simple as having an egg or two for breakfast.

“We often find in studies of older adults that there is very little protein in breakfast and lunch meals, so these provide a good opportunity to increase protein intake,” said said Dr Tom Maden-Wilkinson, muscle physiologist at the University of Sheffield-Hallam.

“I would be eager to get the message out that people need to start thinking about this even in their 40s and 50s,” Dr. Williams said. “But I don’t think spiked chocolate bars are the answer.”

The power of protein

The advice from the NHS is that people should eat an average of 0.75 grams of protein per kilogram of body weight per day. This equates to around 45g per day for a typical woman and 55g for a man. While some scientists say we need more than these amounts to keep our muscles healthy, here’s a guide to how much protein is in common foods, per serving:

Chicken breast, a serving of 90 g – 29 g

Steak, a portion of 90g – 28g

Tuna, a typical 160g can, drained – 26g

Egg, large – 9g

Skimmed, semi-skimmed or whole milk, 200 ml glass – 7g

Cheddar cheese, a serving of 30g – 7.5g

Baked beans, a small box of 200g – 10g