Too much protein can crowd out vital nutrients, physiologist warns

Many people need less protein than they may think, and a high-protein diet can displace whole grains, fibre, fruit, vegetables and healthy fats, according to physiologist Jessica Norrbom at Karolinska Institutet, SVT reports.

Protein-focused products have become increasingly popular, including quark, protein water, protein bread, protein ice cream and various supplements.

For people with normal exercise habits, dietary recommendations suggest that 10 to 20 per cent of energy should come from protein. This corresponds to just under one gram per kilogram of body weight per day. A person weighing 70 kilograms would therefore need about 70 grams of protein a day.

People who exercise extensively may need somewhat more, perhaps 1.5 grams per kilogram of body weight per day, Norrbom says.

Eating more protein than this is generally not dangerous for a healthy person, she says. The body can use the additional protein, although it is stored as energy.

For people who train a great deal, Norrbom says it is also important to consume enough carbohydrates and fat. The body can only convert a certain amount of protein for exercise, while muscles primarily use carbohydrates and fat as fuel.

The main risk of consuming too much protein is that it replaces other nutrients the body needs, she says. A balanced diet should therefore include more than protein.