Is it better to drink or eat your protein? Experts reveal if a chicken breast is healthier than a shake - and which powders are best...

Protein is no longer just the preserve of bodybuilders and gym fanatics.These days, there's an extra dose in everything - breakfast cereals, bagels, chocolate bars, and now coffee. Starbucks has introduced protein-enhanced drinks to its UK menu, while Costa has been trialling lattes containing 23g of protein – roughly the same amount you'd find in a small chicken breast.And this month, Caffè Nero joined forces with sports nutrition brand Myprotein to launch iced lattes containing up to 25g of protein, promising a substantial dose of the muscle-building nutrient alongside your caffeine fix.Alongside carbohydrates and fats, protein is one of the three main nutrients - essential for building and repairing muscles, maintaining supple skin and strong hair, and producing vital hormones.But, can we get everything we need from a daily chicken breast or a couple of eggs? Or is it worth investing in a liquid protein top up? Here, registered nutritionist Emma Bardwell reveals all. Protein is necessary to build and sustain muscles. This includes skeletal muscles, the muscles that allow your heart to beat and the muscles that open up your airways to breatheHow much protein should I eat per day?The NHS recommends that adults eat 0.75g of protein per kilogram of body weight a day, which works out at around 52.5g for someone who weighs 70kg - the equivalent of two medium chicken breasts or two scoops of protein powder. However, Bardwell suggests that healthy, active midlife and older adults consider consuming around 1.2–1.6g of protein per kilogram of body weight daily, depending on their activity levels and circumstances.This is because with age, the body becomes less efficient at using dietary protein to build and maintain muscle, meaning we need more to preserve strength and mobility.This could see someone’s protein need increase to 84–112g daily - the equivalent of three and a half tins of tuna or a large pot of Greek yoghurt.But there's a risk - too much protein in the diet can overload the kidneys. Experts say the danger mostly concerns those who already suffer kidney problems; these patients are advised to limit protein to around 0.55-0.8g/kg per day - roughly 52g for the average woman, and about 64g for the average man.However experts have recently warned of a rise in otherwise healthy, young people developing kidney stones as a result of super high-protein diets. Kidney stones are small, hard lumps of salts and minerals such as calcium that can be otherwise symptomless until they move into the ureter – the tube carrying urine from the kidney to the bladder, where they cause excruciating pain. If they become lodged there, it can be life-threatening.‘Eating a lot of protein makes urine acidic, raising the amount of uric acid in it but also increasing calcium (partly because the acid leads to calcium being released from bone), and lowers citrate, a stone inhibitor (found naturally in the body). This means stones form more easily,' said Vimoshan Arumuham, a consultant urological surgeon at University College London Hospital.Protein shakes versus everyday foods – which is healthier?A typical protein shake delivers around 20–25g of protein, while 100g of cooked chicken breast provides approximately 32g.Two large eggs contain around 12–13g, meaning you'd need to eat four to get roughly the same amount as a shake (which can be rustled up in seconds compared to the length of time it takes to bring a pan of water to the boil). Starbucks, Costa and Cafe Nero have launched drinks with added protein'Your body can digest and absorb protein from shakes and solid food equally,' Bardwell explains.Gram for gram, protein powders can actually work out cheaper than ordinary foods. Four large free-range eggs from Tesco will set you back £1.40 and provide around 31g of protein.Getting the same amount from Sainsbury's own-brand protein powder costs approximately £1.12 – a saving of 28p.However, the eggs also provide other nutrients, including choline and vitamin B12, which the powder may not contain.What fills you up more, shakes or whole foods?'Solid foods tend to be more filling than liquids, partly because chewing and time spent eating help feelings of fullness,' Bardwell explains.'A protein shake might contain 25g of protein, but it doesn't necessarily keep you as satisfied as a meal containing the same amount, particularly if that meal also has fibre and healthy fats.''Whey protein is digested relatively quickly, whereas protein from whole foods tends to be digested more slowly because it's part of a more complex food.'A protein shake can contain hundreds of calories, yet may not keep you as full as a frittata with beans – something worth considering if you're trying to lose weight.One of the strongest arguments for eating protein-rich foods instead of relying on shakes, bars and powders is that they provide considerably more nutrition than protein alone.Greek yoghurt supplies calcium and vitamin B12, eggs contain choline, and oily fish such as salmon provide beneficial omega-3 fats.These ‘natural added extras’ are particularly relevant when it comes to fibre, which supports digestive health and is associated with a lower risk of several chronic diseases, including bowel cancer.Most UK adults consume substantially less than the NHS’ recommended 30g of fibre daily. There’s a risk that replacing meals with protein shakes could further reduce opportunities to up your fibre content.Whey, casein, soy and pea – which protein is best?Anyone who has ventured into the supplement aisle will have encountered a bewildering selection of products promising everything from faster recovery to healthier skin and hair. Among the most popular is whey, a milk-derived protein containing all nine essential amino acids.Many sports nutritionists consider it the gold standard due to its high quantity of leucine - the amino acid that triggers muscle protein synthesis.Casein, another milk protein, is digested more slowly but can also support muscle maintenance and growth, particularly if taken at night, before bed.Then there are whey isolates, which undergo additional filtration to remove more fat and lactose, and hydrolysed proteins, which have been partially broken down to speed up digestion.'Unless you have a particular medical or digestive need, there's little convincing evidence that this translates into better results for the average person,' says Bardwell of hydrolysed protein.Soy contains all nine essential amino acids, while pea protein is lower in some of them. But eating a variety of plant proteins throughout the day can make up the difference.READ MORE: Can a low-carb diet really shift a stone in a fortnight?