Actually, I don't know. All I do know is how to give my body the same kind of care I give my car and my house. Decent fuel, decent maintenance, sensible use. If I do that, I hope it'll repay it with as much health as it can give.
So let's talk about fuel. Food and drink.
If you read my article 'On Bodies', you'll know that I think people come in a wide range of shapes and sizes. This 'standard serving' stuff that nutritionists talk about is useless. People aren't all the same, they don't all need so many grams of this, so many litres of that.
I use the hand as a measure. Why? Because if you're a small build, your hand is small. If you're a large build, your hand is large. It's a measure that adjusts to suit you.
Each person needs the following:
Vitamins and minerals.
Trace amounts of fats and oils.
Protein is available from animal sources, such as meat, fish, eggs and milk. It is also available from plant sources, most commonly seeds. The usual seeds humans eat are legumes and grains, and in combination, one legume plus one grain will provide a full set of proteins humans need.
Vitamins and Minerals
We humans need a bewildering variety of vitamins and minerals, and get most of them from plants. I have a mnemonic which ensures I get them all: I make sure I eat each part of a plant at least three times over the course of a week.
To eat roots, I eat potato, carrots, swedes, turnips, or onions.
Stems are celery, asparagus stalk, broccoli or cauliflower stalk, and rhubarb.
Leaves are easy to recognise: lettuce (any variety), spinach, cabbage and brussels sprouts are all leaves.
Flowers are harder to recognise, but broccoli and cauliflower are both flowers. We eat very few flowers.
Green beans are seed pods and seeds (the seeds inside the pods).
Seeds are all grains and legumes, most nuts, and many spices.
Fruits are tomato, pumpkin, and squash, as well as all the things we call fruits at the grocer's.
If you aren't sure which part of a plant a fruit or vegetable is, ask your grocer. A specialty grocer can also give you advice on how to prepare anything in his or her shop.
Fruit and vegetables are best fresh, and start to lose nutrients from the moment they're picked. Freezing, canning or drying preserves most of the nutrients.
Herbs and spices also contain vitamins and minerals. Flavour your food with a variety of different herbs and spices: it increases both the 'yum' and the nutrition factor.
Fibre is found in fruits and vegetables, and is in fact the indigestible part of the plant. It helps signal when you've eaten enough (by making you 'feel full'), helps your body digest the rest of the plant, and then acts like a gentle cleaning sponge as it goes through your digestive system.
Energy in food comes from carbohydrates, fats, and (to a small degree) proteins. Carbohydrates are found primarily in fruits and vegetables, and have been refined by animals into honey, and by man into sugars such as 'sugar' aka sucrose, glucose, and corn syrup. We don't actually need the refined stuff, it just tastes good. Our bodies are good at doing the refining.
Fats and Oils
There are certain fats and oils which the body requires. Fruits, vegetables and lean meats actually provide them in sufficient quantity for health, though certain oils are better for the body and brain than others. Exactly which are best is still a matter of study, but in the interim I'm splashing a bit of semi-refined olive oil on my salads.
Or rather, any liquid that is mostly water, and most foods. You'll feel the lack of it more than you'll feel an excess. Dehydration symptoms include dry mouth, dry eyes, dark urine, tiredness, headaches, dizziness, or hangover-like symptoms.
It's easy to experiment and find out if you're feeling icky because of dehydration: drink water. If the ickiness eases or goes away, you were dehydrated and you can prevent future occurrances by drinking more water.
If you get your protein from an animal source, you need about enough lean meat to cover the palm of your hand each day, at about the thickness of your hand.
If you get it from legumes and grains, eat about a handful of each daily.
If you eat dairy foods, you can get enough calcium for your bones from three serves of dairy a day. One serve is a piece of cheese about half the size of your palm, or a glass of milk or yoghurt. (Milk or yoghurt are too messy to measure with your hand.)
If you don't eat dairy foods, you'll need to make a special effort to get calcium. Supplements are available, or you can get it from some tofu, some green leafy vegetables, some nuts, or the edible bones of some fish. See a nutritionist, or a good vegan information source.
Eat about seven handfuls of vegetables or fruit a day, and try to eat a wide variety of them over the course of a week. This will give you enough fibre and enough vitamins and minerals.
Eat a range of herbs and spices over the course of the week. This will help you get trace elements you might otherwise miss out on.
We do not need to eat anything specifically for the energy. We did when most people were doing heavy work all day every day: a pioneer going out to weed and plough a farm with no machinery, or chop trees with a hand axe, needs the energy provided by a traditional farmer's meal laden with syrup and fried in lard or oil.
If you're doing that sort of heavy work or heavy exercise, please consult a nutritionist. Modern , healthier versions of the farmer's breakfast are available.
If you aren't doing unusually heavy work or exercise, your hand-measured portions of fruits, vegetables and meats will provide you with plenty of energy.
NOTE: These portion sizes are based on the minimum exercise given below. If you do more exercise, you'll need a little more of the fuel, protein, vitamins and minerals than is stated here. How much more will depend on the amount of exercise, but if you learn to listen to your body, it will tell you.
Is that enough?
Learn to recognise the hunger that comes from the guts or the muscles, rather than from the mouth or the 'appetite' part of the brain.
Your gut-hunger is a bit slow to realise it's fed, so eat until you're still just a little bit gut-or-muscle hungry, then put the rest of your meal away in the fridge. If you're still hungry half an hour later, come back and eat more.
Your body also needs exercise.
How much exercise you give it will affect how much of each type of fuel you need - just like your car needs more petrol (gas to some) if you run it further.
My minimum exercise standard for a body:
- make each joint go through its full range of motion.
- stretch each muscle bundle.
- go for a walk which challenges you slightly. Measure your distance by fatigue: you should feel a kind of pleasant tiredness when you return through your front door. Do it at a speed where you can speak comfortably, but not sing.
If you want to actually improve your health, or to shape your body, you'll need more exercise. But for maintenance, that will do.
You will have noticed that I haven't discussed chocolate, iced pretzels, doughnuts, cake, or any other treat foods. Your body doesn't need them.
You do. Or at least, you might. Eat them, but eat only as much as you actually enjoy. Stop as soon as you realise you're eating it just because you paid for it. Better to waste the extra than to put it on your hips as fat.
Here's a rule of thumb: everything you eat must pay for itself, either in nutrition or enjoyment. Follow that rule, and you should be fine.
If you are doing a lot of exercise, have a metabolic problem, or find that following these rules of thumb causes you to gain or lose weight, check with your doctor.
Heavy exercise changes the rules, and so do disorders such a diabetes and thyroid problems. Your family doctor will be able to help you find the rules of thumb appropriate to your own body and lifestyle.