Nutritional Research

Protein

Summary

  • Protein is the second most abundant compound in the body, after water. About 40% of this will be muscle.
  • All human cells and tissues contain protein, therefore protein is essential for cell growth and repair, and the maintenance of good overall health.
  • Protein is made of long chains of “amino acids” found directly in foods, or made by the body.

Daily protein needs:

Active adults need about 0.75g of protein per kilogram bodyweight per day.

So a 60kg woman would need about 45g of protein per day.

And an 80kg man, about 60g.

Children and teenagers:

The US government recommends about 35 grams of protein per day for girls aged 9 to 13 and 45 grams of protein each day for girls aged 14 to 18.

Teenage girls should aim to consume at least the above RDA (recommended daily amount) for protein; active girls may need additional protein to maintain or repair muscle tissue after physical activity.

Teenage boys need about 45-60g of protein per day.

Protein content of different foods

A 200g steak contains about 50g of protein.

Protein from animal sources (meat, fish, eggs and dairy products) contains the full range of essential amino acids needed by the body

However, vegans and vegetarians can get all the amino acids they need by combining different plant sources of protein, e.g. pulses and cereals.

Energy Bars contain about 4-10g of protein, and a Protein Bar about 10-20g.

Protein and Weight Management

Protein-rich foods tend to make people feel fuller than foods rich in carbohydrates or fat. So including a lean source of protein with a meal can help to minimise feelings of hunger and decrease overall calorie intake.

When reducing calorie intake in order to lose weight, it will be necessary to reduce intake of some foods but it is a good idea to maintain intake of low-fat, protein rich foods.

In the context of a lower energy intake, this will result in a relatively high proportion of energy coming from protein in the diet, but will not represent an increase in the absolute amount of protein consumed or require the other food groups to be cut out of the diet.

Source: British Nutrition Foundation

https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?start=3

Protein content of different foods

A 200g steak contains about 50g of protein.

Protein from animal sources (meat, fish, eggs and dairy products) contains the full range of essential amino acids needed by the body

However, vegans and vegetarians can get all the amino acids they need by combining different plant sources of protein, e.g. pulses and cereals.

Energy Bars contain about 4-10g of protein, and a Protein Bar about 10-20g.

Carbohydrates

Summary

Carbohydrates are key components in the diet, made up of

  • sugars
  • starchy carbohydrates, like potatoes, bread, rice and pasta 
  • dietary fibre
    • Sugars
      • Intrinsic sugars: sugars in whole fruits and vegetables.


    • Extrinsic sugars: Honey, fruit juices, table sugar and confectionery

    • Starchy carbohydrates provide an important source of energy (calories)
    • Fibre is important for digestive health.
    • At least half the energy in our diets should come from carbohydrate, mostly as starchy carbohydrates

Daily carbohydrate needs

Daily carbohydrate needs:

  • It’s important to keep track of your energy (calorie) intake from carbohydrates. The total for a UK adult should be about 260g divided between:
  • non sugar (starch and fibre): about 170g
  • total sugars: about 90g

High in sugar means more than 22.5g of total sugars per 100g 


Low in sugars means
5g of total sugars or less per 100g

Lipids (Fats)

Summary

Why we need some fat:

A small amount of fat is an essential part of a healthy, balanced diet.

  • Fat is a source of essential fatty acids, which the body can’t make itself. 
  • Too much fat in your diet, especially saturated fats, can raise your cholesterol, which increases the risk of heart disease.  
  • Current UK government guidelines advise cutting down on all fats and replacing saturated fat with some unsaturated fat.
  • Fat helps the body absorb vitamins AD and E. These vitamins are fat-soluble, meaning they can only be absorbed with the help of fats.
  • Any fat not used by your body’s cells or to create energy is converted into body fat.
  • Likewise, unused carbohydrate and protein are also converted into body fat. 
  • Most energy and protein bars will be relatively low in fat

To be sure of the fat content and the energy content, remember to check the nutrition label on the packet.

Humectants

Summary

  • Foods that need to be kept moist risk potential bacterial growth.
  • Moisture in food can be controlled by removing it through dehydration or chemically binding it with humectants.
  • Sugar and salt are the oldest and most widely used humectants.
  • Examples of other commonly used humectants include glycerin, honey, sugar alcohols, glucose syrup, egg yolk, egg white, molasses and alpha hydroxy acids such as lactic acid.

Sweeteners

Summary

  • Sorbitol – This sweetener is derived from glucose and contains 60% of the sweetness of sucrose.

  • Xylitol – Derived from xylose, xylitol is 100% as sweet as sucrose.

Emulsifiers

Summary

Emulsifiers help water moisture and oils in foods to mix.

The emulsifiers that are used come from both natural and synthetic sources. They include:

Lecithins (E322) are mixtures usually extracted from sources such as egg yolk, sunflower or soybeans.

Esters of monoglycerides of fatty acids (E472a-f) are made from natural fatty acids, glycerol and an organic acid such as acetic, citric, lactic or tartaric.

The fatty acids are usually from a vegetable source, though animal fats can be used.

Mono- and diglycerides of fatty acids (E471) are semi-synthetic emulsifiers made from glycerol and natural fatty acids, which can be from either plant or animal sources. They are used in products like breads, cakes and margarines.

Look for natural emulsifiers.

Mixed Tocopherols

Summary

These are natural antioxidants used for the preservation of fats, oils and protein meals, sometimes present in energy bars.

They are made up of chemicals related to Vitamin E.

Bulking Agents

Summary

Bulking agents such as starch are additives that increase the volume of a food without affecting its taste.

Some bars have them. We try to avoid them unless the bars’ other ingredients are so good that we are happy to stock them.