How much protein do we need to eat?

Adults in the UK eat nearly fifty per cent more protein than they need. Protein for many, is a mysterious nutrient which has something to do with building muscle and helping with weight loss. But there is so much more to it than that. In this post we are going to look at what protein does in the body, how much do we need and whether protein from animal foods is better than protein from vegetables.

The basics

Proteins are chemical structures made up of building blocks known as amino acids. There are about 20 amino acids found in our mixed diet of animals and plants. Eight of these amino acids are essential for making proteins in the adult human body. The other amino acids can be reconfigured in the body from these eight.

Function of protein in the body

Proteins are present in every cell of the body and are required for the growth and repair of human tissue such as muscle, skin and blood.

How much protein do we need?

Adult men require approximately 56g protein per day and women 45g (0.75g per kilogram of body weight). There is an extra requirement for growth in infants and children and for pregnant and breast feeding women. Average daily intakes of protein in the UK are 88g for men and 64g for women, which is more than sufficient.

What happens if I eat more protein than my body needs?

When the body has met its requirement for protein any extra is converted into dietary energy, which if not used will be stored as body fat.

Dietary protein in the UK provides about 15% of the energy (kcal) eaten.

Plant verses animal protein

Both plant and animal foods contain protein. Animal protein contains all the essential amino acids required by humans. So do plant foods but they must be eaten in combination such as a cereal (e.g. bread) and pulses (e.g. baked beans) so the amino acids of each protein complement the other. If vegetarians and vegans eat a variety of vegetable proteins, the quality of protein is as good as in a diet comprising meat, milk, fish and eggs. Good sources of plant protein include nuts, seeds, pulses and soya products. High protein foods like cheese and some meat are also high in fat and energy and their intake should be limited.

Protein content of common foods

How do I include enough protein in my diet?

Adults and children need to eat two to three servings of protein every day.

A typical portion is:

• 100 g of lean, boneless meat

• 140 g of fish

• 2 medium eggs

• 100 g cooked pulses

• 3 tablespoons of seeds or nuts

Protein and weight management

Protein-rich foods tend to make people feel fuller than foods rich in carbohydrates or fat. Including a lean source of protein with a meal can help to minimise feelings of hunger and decrease overall energy intake. However there are safety concerns about very-high-protein diets that involved cutting out other food groups.

Some high protein, low carbohydrate diets claim to be effective at producing weight loss despite a high fat intake from fatty meats and full fat dairy products. These diets remains contradictory to current healthy eating messages. Regardless of the composition of the diet, weight loss only occurs if energy intake is less than energy output and a negative energy balance is achieved.