Will the trendy new protein-rich foods really make you slim?

YOU’VE done low-fat, ticked off low-sugar tried low-carb . . . but to lose weight and stay healthy you might actually need to eat more.

That’s the counter-intuitive science behind the latest big food trend to hit supermarket shelves.

Some experts now believe women in middle age and beyond don’t eat enough of one particular food type — protein. Without sufficient protein, we not only lose muscle mass that helps us burn calories efficiently, we also snack more, because protein quashes hunger more effectively than any other kind of food.

To keep fit, strong and lean, goes the theory, we all need to eat more of it. Which explains the latest craze to fill our fridges with protein-enriched foods.

Until recently, protein-focused foods were solely the preserve of body builders, who used tubs of whey powder to build and maintain muscle.

But in a few years they’ve moved from niche to mainstream — today you can buy everything from protein-enriched bread and breakfast cereals to Cup-a-Soups, cereal bars, smoothies, pizzas, chocolate and even milk.

Protein is such a big deal, food manufacturers have begun boasting about the protein content of foods that are naturally high in it, like chicken and cheese, emblazoning it across packaging and shop displays.

MEANWHILE, a survey for The Grocer magazine shows the British eat a record 69g of protein a day — significantly higher than the recommended amount — and although there are no equivalent surveys on Irish intake, you can be sure we’re not far behind. However, guidelines recommend that the average adult should eat less than this — about 55g of protein a day, or about 0.75g per kg of body weight.

So what’s driving this hunger for protein? Clinical dietitian, Sharmain Davis, says there’s an argument in scientific circles that the official guidelines are out of date and set too low.

‘That 0.75g of protein per kg of bodyweight does not appear to be enough if you’re active, if you’re on a diet, or you’re elderly,’ she says.

She points to research showing that dieters should eat more like 1.6g of protein per kg of bodyweight, which would be 102g a day for a 63.5kg (ten stone) woman.

Indeed, it’s now thought that if you are not losing weight while on a conventional low-calorie diet, you’re probably not eating enough protein, since it is protein that revs up a sluggish metabolism and helps you burn more calories.

One Canadian study of overweight women on a diet found the group eating more protein (1.3g per kg) lost more fat and gained more lean mass (including muscle) than those consuming the recommended daily amount.

Protein fills you up, too. Another study showed that when people ate 30% of their daily calories as protein (rather than carbs or fat) they automatically cut their overall intake by 441 calories a day.

And older women are especially at risk of protein deficiency. After the age of 40, muscle mass and strength begins to decrease by about 8% per decade — a condition called sarcopenia — meaning the averagely sedentary woman is likely to have lost 15lb of muscle by the time she reaches her late 50s. Muscle that is quite likely to have been replaced by fat.

So it’s easy to see why midlife women are suddenly paying attention to protein levels.

But how do manufacturers cram all this extra protein into food? And how healthy is it?

Nutrition scientist Dr Alexandra Johnstone says it depends on the product.

Weetabix Protein, for example, look like standard Weetabix but have 7.6g of protein for two biscuits compared with 4.5g for normal Weetabix. Most of the added protein comes from wheat gluten, plus smaller amounts from rice flour, wheat starch and wheatgerm, in addition to the main ingredient of wholegrain wheat. High-protein yoghurts are usually made from quark, a naturally high-protein soft cheese, and cereals in bars and breakfast products may be sprayed with whey protein, a high quality protein extracted from milk. Also look out for added pea flour, chickpea flour, soy or nuts and seeds in the ingredient list, says Dr Johnstone. However, she says added-protein foods often have added sugar, because plant proteins like soy and pea tend to be quite bitter or have an earthy flavour.

THE Weetabix Protein has 1.9g of sugar per two-biscuit serving compared with 1.7g in regular Weetabix — not too bad. But the Weetabix Protein Crunch Chocolate has 6.6g for a smaller 30g serving.

That’s the real danger of these foods, says nutritionist Fiona Hunter. ‘Because protein is enjoying a “health halo” at the moment, people see protein on the label and think it’s automatically good for them, but they fail to look at the sugar, fat and salt the product might contain.

‘Just because a cereal bar says it’s high in protein, it doesn’t make it a healthy way to get your protein. It’s still full of sugar. A Mars Protein bar is still a Mars bar. There are cheaper and more natural ways to get protein into your diet if you feel you need it.’ Such as yoghurt, milk, eggs and nuts, she says.

By law, manufacturers can call a food ‘high-protein’ if 20% of the food’s energy value is provided by protein, and they can call it a ‘source of protein’ at 12%. But even a food labelled ‘high-protein’ may not be particularly high compared with foods naturally rich in it.

‘It shocked me that Cup-a-Soup High Protein met the criteria for a high-protein food,’ says Fiona. ‘It still only provides 4.1g to 4.9g of protein, yet an egg gives you 6g and a hummus and salad sandwich might give you 10g.’

She fears we over-obsess about protein and thinks if you’re not on a diet, the recommended 50g a day is probably enough.

Too much, she says, can cause kidney damage in those with renal problems, and some research suggests suddenly moving to a very high-protein diet can put a strain on the kidneys. And if you rely on high-sugar products like cereal bars or fruit yoghurts for protein, you could put on weight.

‘I’d advise people to read the labels carefully and beware the marketing hype before parting with their money for protein-enriched foods,’ says Fiona.