"...all doctors should be able to diagnose and treat nutritional deficiencies."

Royal College of Physicians. Nutrition and Patients: A Doctor's Responsibility. London 2002

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Energy and Protein

Main page | Energy & Protein | Vitamins | Minerals | Essential Fatty Acids

Energy

Energy is the most vital component of food intake and hunger is the stimulus to increase our energy intake.  Our requirements depend upon age and physical activity.  All foods provide energy but their content may vary widely and our choices of energy source can have profound effects upon our intake of micronutrients (vitamins and minerals) as well as our health.
Energy in food is measured as kilocalories (kcal), which in common use is often abbreviated, incorrectly, to calories (one thousandth of a kilocalorie). 
The alternative measure for energy is kilojoules with 4.184 kJ = 1.0 kcal.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements kcal/day
2,550
1,940
Mean Intakes kcal/day – NDNS data
2,313
1,632

Content of Individual Foods

Food
Energy Content (kilocalories per 100g)
Wholemeal bread
217
White bread
219
Shredded wheat
332
Porridge made with water
46
Muesli, no added sugar
366
Frosties
381
Corn Flakes
376
Semi-skimmed milk
46
Whole milk
66
Cheddar cheese
416
Cottage cheese
101
Olive oil
899
Sugar, white
394
Beef mince, extra lean
177
Lamb leg, roast
203
Chicken roast, average
177
Cod, baked
96
Mackerel, grilled
181
Potatoes baked, flesh and skin
136
Peas, petit pois, frozen, boiled
49
Cabbage, boiled
16
Carrots, boiled
24
Cucumber, raw
10
Tomatoes
17
Sweetcorn-on-the-cob
111
Apples, raw
47
Bananas
95
Oranges
37
Hazelnuts
650
Peanuts, roasted and salted
602
Mars bar
473
Cola
41
Orange juice, unsweetened
36
Beer, bitter best
33
Red wine
68
Sweet white wine
94
Spirits
222

Protein

Protein is an essential macronutrient that provides component amino acids that are released during the process of digestion.  Some amino acids that the body requires cannot be manufactured and thus it is essential that we eat protein-rich foods in order to obtain them.  Proteins can be provided by both animal as well as vegetarian sources but vegetarians will need to eat from a variety of sources to obtain all of the essential amino acids whereas animal sources are normally complete.  There is a daily requirement for protein which is increased during periods of growth and illness.  As a rule protein-rich foods are also rich in other nutrients and are thus a sought-after component in most people’s diets.
Any excess of protein can be used as an energy source or converted into and stored as fat. 

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements g/day
44.4
36.0
Mean Intakes g/day – NDNS data
88.2
63.7

None or minimal amounts are provided by nutritional supplements unless a specific high-protein food supplement is being taken.

Content of Individual Foods

Food
Protein Content (gm per 100g)
Wholemeal bread
9.4
White bread
7.9
Shredded wheat
11.2
Porridge made with water
1.4
Muesli, no added sugar
10.5
Frosties
5.3
Corn Flakes
7.9
Semi-skimmed milk
3.4
Whole milk
3.3
Cheddar cheese
25.4
Cottage cheese
12.6
Olive oil
0
Sugar, white
0
Eggs (chicken), boiled
12.5
Beef mince, extra lean
24.7
Lamb leg, roast
29.7
Chicken, roast, average
27.3
Cod, baked
21.4
Mackerel, grilled
20.8
Pasta, white, boiled
3.6
Potatoes baked, flesh and skin
3.9
Peas, petit pois, frozen, boiled
5.0
Cabbage, boiled
1.0
Carrots, boiled
0.6
Cucumber, raw
0.7
Tomatoes
0.7
Sweetcorn-on-the-cob
4.2
Apples, raw
0.4
Bananas
1.2
Oranges
1.1
Hazelnuts
14.1
Peanuts, roasted and salted
24.5
Mars bar
4.5
Cola
Trace
Orange juice, unsweetened
0.5
Beer, bitter best
0.3
Red wine
0.1
Sweet white wine
0.2
Spirits
Trace

Main page | Energy & Protein | Vitamins | Minerals | Essential Fatty Acids




Copyright Dr. Alan Stewart M.B.B.S.M.R.C.P. (UK)M.F. Hom.
47 Priory Street, Lewes, East Sussex. BN7 1HJ
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