CR "How To"

By Steve Chambers <>
(C) Copyright 1996


It´s worth getting a medical checkup before you embark upon a calorie restriction programme. Tell your doctor what you´re planning. It´s unlikely that he´ll know anything about CR as an anti-aging tool so don´t expect too much support. He will, however, be able to make sure you don´t have some condition that will prevent you practising CR. And for your own reference, you´ll want the results from these tests:
If you really want to convince your doctor about the benefits of calorie restriction, get these tests again after you´ve been doing it a year. Let him compare them.

The next step is to estimate your daily calorie requirements. I say estimate, because everyone is different and only trial and error will tell you how much food you need. Take what you believe to be your ideal weight (most people have such a figure in mind), convert it to kilograms, and multiply it by 25. This is your estimate for daily calories under the CR regimen. If you really have no idea what your "ideal weight" should be, use your newly discovered body fat % to guide you. Calculate what your weight would be if you had 10% fat (men) or 15% fat (women).

Getting Started

I recommend starting with a three to five day "Get to know your stomach" fast. This isn´t a fast in the true sense of the word as you´ll be eating a piece of fruit and a tablespoon of fish or flax oil twice a day to assist the absorption of your supplements. You´ll also be drinking diluted fruit or vegetable juices to combat energy lows. These can be heated if necessary to help keep you warm.

During this fast you´ll learn how little you can eat and still function. You´ll discover that hunger pangs don´t mean that you need food - you may even come to like the feeling that you used to call hunger. You´ll feel how sharp and alert you can be when your stomach is empty. Towards the end of your fast you´ll feel the signs that *really* mean you need some food. Your signs may be weakness, difficulty in concentrating, or perhaps a lethargy that diluted juice won´t fix. The fast will also help you in to your new lifestyle by shrinking your stomach.

Carry on with your normal routine while you fast. You´ll be able to engage in most activities as if you were eating normally. Strenuous exertion, however, will tire you more quickly and you´ll need to limit it.

You may find the first few days of your first fast quite difficult. Your body will initially behave much like a spoiled brat who´s had his toys taken away. But you´ll feel much better when your stomach has learned that your head is the boss. If you ever fast again you´ll find it much easier. Some practitioners prefer to do their calorie restriction by fasting in this way for two days every week and eating more than their daily calorie allowance on the other five days.

To allow your body to readapt, you should finish your fast with a small quantity of nutritious food and take two days to build back up to your full daily intake.

Fine Tuning Your New Lifestyle

Test out your estimated daily calorie allowance. Don´t try too hard to stick to it during the first two months. Even with a relaxed attitude to compliance you´ll probably find yourself losing weight quite quickly. By the fourth month you should have a good feel for whether your calorie allowance is appropriate. If it seems too extreme for you, relax it a little.

Monitor the effects. Weigh yourself once a week at the same time of the morning. Don´t lose weight too quickly - from the third month on you should aim to lose no more than 1% of your body weight per month. Your body needs time to adapt or it won´t get the life-extending benefits. If you´re losing too fast, eat a little more until the loss rate is less than 1% per month.

Eventually your weight will stabilise. For some it will be as little as 10% below where they started, for others much more. At that point you may wish to consider further reducing your calorie intake. How far? Within reason, the less calories you eat the better - and it´s quite possible to get by indefinitely with less than 20 calories for every kg of body weight. Down to this level, the less you eat the longer you´ll live - so long as you don´t malnourish yourself.

It´s likely that you´ll become quite thin, but if not don´t be tempted to reduce your calorie intake any lower than this. Rodent studies show that it´s not how thin you are that matters - it´s how much you eat. Genetically "fat" mice on a calorie-restricted diet are as big as some other fully fed mice - but they live 50% longer.

What to Eat

Low calorie, nutrient dense foods are the secret to a calorie restricted lifestyle. This means avoiding high calorie "empty" foods like sugar, honey, sweets, chocolate, white flour bread, buns and cakes. Fats are the most concentrated calorie source - nine calories per gram compared with four calories for carbohydrates and protein. Animal fat (especially the visible stuff), butter, cheese, nuts, oils and oil-based dressings and whole milk products should be kept to an absolute minimum. Alcohol is another source of empty calories - seven calories for every gram.

Many foods promoted as being healthy can be poor choices for a CR lifestyle. A glass of juice, for example, can contain 100-200 calories. Dilute the juice - or even better, eat the whole fruit or vegetable and drink water instead. Most processed foods are unnecessarily high in sugar and fat. If you must choose a packaged food, read the label. Pick products made from whole foods and check for added sugars, fats and oils.

The label will also tell you how many calories the product contains. Use this figure to help you choose between similar products. Don´t let terms like KJ (kilojoule) and Kcal (kilocalorie) put you off. When discussing food, a kilocalorie is the same as a calorie and you can just divide kilojoules by 4.2 to get calories.

It´s important to get enough protein, but most of us get way too much. Protein is a "dirty" fuel - try to discourage the body from using it for energy. You´ll achieve this if you only eat around a gram of protein for each kilogram of body weight. The protein needs to be "complete", however - its amino acids balanced so your body can build its own proteins with them. Skim milk products, soy products, lean meats and fish are good sources. A good mix of grains and vegetables (especially beans) will also give you the right amino acid balance.

Use the food pyramid to guide your food choices - but try to chop the top off.


In today´s fast food, instant gratification society it´s difficult for CR practitioners to stay "on-track". Here are a few tips:

Monitor your calorie intake regularly, but not obsessively. You´ll want to count your day´s calories quite often in the early stages, but after a few months you won´t find it so necessary. With a little experience you´ll quite quickly be able to estimate the calories in what you´re eating. You´ll find too, that you´ll (almost subconsciously) tend to eat close to the amount you should.

Try to eat foods that suppress rather than stimulate your appetite. Stomach "fullness" is an important hunger cue - so eat bulky, high fibre foods. Surprisingly, foods that the body quickly turns to sugar can increase your hunger. That´s why it´s so popular to serve bread before a meal. By avoiding these "high glycemic index" foods you can reduce food cravings.

If you have a sweet tooth, try to re-educate it. You can use aspartame in teas and coffee but you should avoid the large amounts in diet soft drinks (sodas) - we just don´t know its long-term effects.

Don´t eat when you´re not hungry. Treat "meal-times" as an arbitrary construct that you no longer have use for. And don´t feel you have to eat just because everyone else is. Much of what most of us call hunger is a Pavlovian response to the clock, the smell of food or the sound of plates clanging.

If you´re not enjoying what you´re eating, don´t finish it just because you´ve bought it or because your host has served it. Don´t feel guilty, there´s no such thing as wasting food - nature is getting it back whether you eat it or not. And people are starving in the third world for reasons of politics - not because you´ve got their food.

Make an effort to condition for yourself some *new* eating-related feelings. Learn to hate feeling full. Dwell on your guilty feelings if you´ve overeaten or eaten wrongly. And when you feel hungry, just imagine how much good it´s doing you.

Avoid temptation. Don´t bring undesirable foods into your house and don´t shop for food when you´re hungry. Avoid buffet or smorgasbord restaurants, you always feel like you want to get your money´s worth. Don´t sit near snack bowls at parties. Don´t even think about food unless you´re preparing it or eating it. If you think about it, you´ll want it.

Take the time to enjoy your food. Eat it slowly, savour ever mouthful, every unique taste. Notice how good it tastes when you´re left wanting just a little more. Eating is a great pleasure, and there´s no reason why you can´t extract even more pleasure from it than you did before.


It´s important to remember that CR has been thoroughly tested on laboratory rodents but not on humans. Although there´s a wealth of evidence to show that it works for humans and that it´s safe, we still can´t be totally sure. Watch, and listen to your body as it goes through its changes. See your physician for *anything* that you think might be out of the ordinary.

Any testing your physician does should show you to be in the peak of health. One exception, however, is your blood leukocyte count - it may be below the normal range. This is quite normal for CR practitioners and should not be cause for concern by itself.

Among the changes you´ll experience is a reduction in your average metabolic rate. So-called weight-loss experts will draw parallels with yoyo dieting and suggest that this is detrimental. Not so - it´s a key part of the CR effect and it simply means that your body is using it´s food more efficiently. The result is fewer damaging by-products and less wasted heat - factors that may contribute a life-extending effect. A reduced metabolism will, however, make you gain weight more easily should you return to your old eating habits.

You´ll also notice a greater sensitivity to cold, partly the result of reduced resting metabolism and partly because you´ll have less fat for insulation. Hot beverages and hot diluted juices can help. To compensate, you´ll find that you have an increased tolerance for heat.

There´s uncertainty about the effects CR might have on osteoporosis in later years. For this reason young women should be particularly careful when practising CR. If it leads to irregular periods you can be sure that it´s compromising your bone density - not to mention your chances for conception. And CR is not-at-all appropriate during pregnancy. It´s probably best that women undertake only mild restriction until thirty. During the post-menopausal years, less body fat will mean less of the extra-ovarian oestrogens that minimise bone loss. Despite this, CR will probably *strengthen* middle-aged bone - by delaying menopause. Bone density scans at thirty, forty and at least twice during the climacteric will tell you whether you need to take any action.