2019-04-20_New_Scientist

20 April 2019 | NewScientist | 41

is being able to stick to cutting calories.”
Products touting extra protein can
sometimes come laden with extra helpings
of sugar, too (see “Read the small print”, page
39). “My worry with products like high-protein
sugary cereals and high-protein chocolate bars
is that people will assume they are healthy,”
says Gray. “Putting a bit of protein in a
chocolate bar does not make it healthy.”
Another thing that rarely gets mentioned
is the risk associated with stuffing yourself
full of protein. There are good reasons why
the UK Department of Health advises adults
to avoid consuming more than twice the
recommended daily protein intake.

Too much of a good thing

When the body has more protein than it
needs, the excess is broken down and waste
products are filtered from the blood to be
excreted as urine. Research, albeit mostly in
animals, has suggested that greater protein
intake increases the workload on the kidneys,
which do the filtering, potentially leading to
damage in the long term. This hasn’t been
confirmed in human studies and some
researchers are sceptical. However,
randomised controlled studies, the gold
standard when it comes to medical evidence,
have shown that people with kidney disease
who are put on low-protein diets are less
likely to have renal failure or die from
complications linked to their condition
than those on normal diets.
Excess protein also leads to elevated levels
of urea in the blood, and some research has
linked consistently high levels to increased
risk of cardiovascular disease. A large, long-
term study published in May 2018 that took
into account other determinants of heart
health, such as exercise and diet, seems to
back this up. Finnish researchers found that
men who reported high protein intake (an
average of 109 grams per day) were 33 per cent
more likely to experience heart failure than
those who consumed the least (a daily average
of 78 grams).
All of which makes you wonder: given the
lack of evidence to support claims made for
protein fortification, not to mention the risks,
why the ever-growing demand?
Marion Nestle, a nutritional scientist at
New York University, says our hunger for
added protein has, in large part, been created
by food companies. “Carbs are out, fats are
out, and paleo and keto diets are hot right
now,” she says. “Protein is all that’s left in the
macronutrient category. These trends go in

cycles. This is about marketing.” Indeed, in her

2018 book, Unsavory Truth, Nestle argues that

the food and drinks industry, especially those

selling protein-heavy products such as meat

and dairy, has distorted nutrition science by,

for example, publishing only results that are

useful in marketing their products.

So despite what you read on supermarket

shelves, or in the fitness magazines that have

played a big role in driving the craze, you

probably don’t need more protein. Indeed,

given the way the body deals with the excess,

most people who splash out on high-protein

water, or any other products from the ever-

growing protein-fortified range, might just

as well flush their money down the toilet. ■

Nic Fleming is a writer based in Bristol, UK

For links to the studies quoted, see the online version

of this article

PROTEIN: ARE YOU GETTING ENOUGH?

(Spoiler alert: almost certainly)

In the UK, adults are advised to eat 0.75g of protein per kilogram of body weight per day. This means men

of average weight should eat 56g and women 45g daily. This can be achieved in just a few snacks and meals

For people regularly lifting weights, the British Nutrition Foundation suggests consuming 1.2-1.7g of

protein per kg per day. Taking the upper end of that scale and using the weight of an average person

just starting out on a strength-training programme, here is how to get what is required

MALE WEIGHTLIFTER

2 eggs on wholewheat toast (21g protein)

Small glass of semi-skimmed milk (5g)

Cottage cheese on wholewheat toast (20g)

Whole chicken breast and lentils (72g)

Handful of almonds (10g)

TOTAL: 128g

FEMALE WEIGHTLIFTER

Porridge (11g protein)

Small glass of semi-skimmed milk (5g)

Chicken sandwich on wholewheat bread (28g)

Handful of almonds (10g)

Bowl of pasta and grilled salmon (31g)

Yogurt and handful of walnuts (16g)

TOTAL: 101g

MEN

Small glass of

semi-skimmed milk (5g protein)

Porridge (11g protein)

Cheese sandwich,

wholewheat bread (15g)

Yogurt and handful of walnuts (16g)

Tuna salad (12g)

Bowl of pasta with chicken (39g)

WOMEN

SOURCES: BRITISH NUTRITION FOUNDATION HTTPS://WWW.NUTRITION.ORG.UK/NUTRITIONSCIENCE/NUTRIENTS-FOOD-AND-

INGREDIENTS/PROTEIN.HTML?START=4 US DEPARTMENT OF AGRICULTURE HTTPS://NDB.NAL.USDA.GOV/NDB/FOODS/