Nutrition

You can go to www.nutrition.org.uk for a comprehensive understanding of the various types of nutrient.  As a simple taster, foods break down into three macro-nutrients (protein, carbohydrate and fat) and about thirty micro-nutrients (vitamins and minerals) of which you only need small quantities.

Any of the three macro-nutrients can be digested to give the body energy.  If you eat more energy than you expend you put on weight especially fat.  If you eat less you lose weight initially surplus fat but when that is gone you lose muscle too.  Protein is especially required for growth and muscle building.  Carbohydrate is predominantly to provide energy.  Fats provide energy too but also have other characteristics.

Within fats (and oils), it has been said, there are the good, the bad and the downright ugly.  The very good – and ones that most people do not get enough of - are the essential oils Omega 3 and Omega 6.  “Essential” means you have to eat it, you can’t make it.  Don’t worry too much about Omega 6, you’ll get enough if you eat vegetables but most people are deficient in Omega 3 and it really is an important foodstuff – it helps with alertness and brainpower, it is calming (for ADHD symptoms), it makes joints supple.  It is found predominantly in oily fish (the old wives’ tale of fish being brain food is actually right) such as sardines, pilchards, salmon, mackerel, fresh (but not tinned) tuna.

The good fats are the unsaturated oils.  “Unsaturated” is to do with the chemical formula and means you could squeeze another carbon atom in there (so now you know).  These are mainly the vegetable oils, liquid at room temperature, like rape seed, olive, grape seed oils.  But not coconut oil / milk – that’s a saturated fat.  You need these fats, it’s a mistake to cut them out too drastically.

The baddies are saturated fats - mainly animal fats, usually solid at room temperature, like butter, cream, lard, red meat fat.  Note that red meat itself contains saturated fat so should appear sparingly in a diet.  These raise cholesterol and that leads to heart disease.  Avoid.

The real baddies are trans-fats also known as hydrogenated fats.  These don’t occur naturally they are produced by bubbling hydrogen through normal fats which makes them go hard.  Until recently they were very common in processed foods.  If you bought food in a box it probably contained trans-fats.  But it is now increasingly recognized that these are killers so they are being phased out.  It’s still worth checking ingredient lists to make sure you get none of it.

Vitamins and minerals are worth attention because deficiencies can cause problems.  Several of these are antioxidants which combat the aging and other damage caused by free radicals (see a discussion of free radicals under “smoking”).  One of the most famous cases was the introduction of lime juice into the Royal Navy diet (why Americans sometimes refer to us as “limeys”) in order to provide vitamin C which prevents rickets.  You can either investigate each one and find out what it’s for (selenium aids memory for example) or accept the received wisdom that if you eat a varied diet including lots of fruit and vegetables you’ll get all the micronutrients you need.   You can get these by taking supplements but the evidence is mixed as to whether supplements are effective (or perhaps even harmful) and there is little doubt that getting what you need from a balanced diet is the better way.

Another important constituent of food, but not really a nutrient because we don’t fully digest it is dietary fibre.  This has important benefits in keeping our systems working and is particularly effective in reducing cholesterol (and so protecting against heart disease) and protecting against some cancers.  Leafy greens are one of the best sources.