What is Calorie Restriction (CR)?
The goal of Calorie Restriction is to achieve a longer and healthier life by
- eating fewer calories
- consuming adequate vitamins, minerals, and other essential nutrients
Extensive scientific research has shown that a CR diet improves the health and extends the lifespan of every species so far tested, including worms, spiders, rodents, dogs, cows and monkeys. We believe that people who adopt a CR diet will see the same results longer life and better health.
How do I Start?
Simply eating less may not improve health or extend lifespan - it can lead to malnutrition
Replace calorie-dense foods with calorie-sparse, nutrient-dense foods
Before worrying about how many calories you're eating, make sure that the foods in your diet provide sufficient nutrition to avoid malnutrition once you begin to restrict them.
Avoid simple sugars and flours.
Sugars and flours generally contain very little nutrition for their calorie content. They also have high glycemic indices, which means that your body absorbs them quickly, leaving you wanting more a short time later.
Eat both green leafy (salad) and other vegetables.
Vegetables -- both green leafy vegetables and non-leaf vegetables -- contain the highest content of a wide variety of nutrients for their calorie content. By volume (and often by calories), vegetables are the major component of many calorie restricted but not nutrient deficient diets.
Carefully select your protein and fat sources.
Both protein and fat are required macronutrients, but their form can have a significant influence on a person's risk factors for a wide variety of diseases.
Make sure your protein intake is sufficient, but not overly abundant.
Common recommendations for total protein intake range from 0.6 to 0.8 grams per kilogram of body weight, and some recommendations are much higher. This is probably a minimum.
Make sure your proteins are complete and balanced.
A complete protein contains all the essential amino acids, while a balanced protein contains all those amino acids in ratios that are most useful to human biophysiology.
- Most animal proteins are complete and well-balanced
There are very few perfectly balanced proteins in our food supply, but animal proteins tend to be among the most balanced.
Unfortunately, animal proteins also tend to include undesirable components. For example, red meat is carcinogenic [PMID: 12376502], and meat (especially red meat) and dairy often contain large quantities of saturated fats. The nutrient density (as always, on a per-calorie basis) of meats is often lower than other choices.
- Non-animal proteins can be balanced by combining different food families
One can get extremely detailed in finding "complementary" foods, but in general, combining legumes (beans) with grains will yield a balanced protein, and rice protein can complement the proteins in vegetables like broccoli, cauliflower, or spinach. Be aware, however, that both rice and grains (even whole grains) have relatively high glycemic indices and relatively low nutrient densities. If you're going to consume these, choose whole grains (not in the form of flours) and long grain brown rice.
Select monounsaturated fats, avoid saturated fats, and consume some Omega-3 fats
Foods containing monounsaturated fats include olive oil, almonds, hazelnuts, and avocados. Most of your fat intake should be from these foods. A very small amount of fat should be in the form of Omega-3 fatty acids, which are found in fatty fish (e.g. salmon) and flax oil. Caution: fatty foods, even healthy choices, are high in calories so be sure that you carefully track your intake so as to stay within your Calorie goal.
Get baseline blood tests done
In order to chart your progress, and to make sure that you are avoiding nutrient deficiencies and other hazards, get at least the minimal recommended blood tests done. You'll want to know these results from before your calorie-restricted diet begins, so that you'll have a baseline for comparison as you move into a calorie-restricted diet.
Reduce calories after improving diet quality (i.e. nutrition)
Once your diet consists primarily of nutrient-dense, calorie-sparse foods, you can safely begin to reduce your total calorie intake. There are some things to consider at this point, if you have not already considered them.
Lose weight slowly
Many people lose weight simply by changing their diet to include more calorie-sparse foods. Even this weight loss should not be allowed to happen too quickly, but by the time you're able to restrict calories, your weight loss should proceed very slowly. There are two reasons for this:
Pesticides and other toxins are fat soluble.
There are many pesticides and other toxins in our food supply that are fat soluble. Human bodies store these toxins relatively harmlessly in body fat. If you lose that fat too quickly, however, all these toxins are flushed into your bloodstream, and your detoxification mechanisms (i.e., your kidney and liver) are unable to remove them [B120YD, 78-80]. You may thus wind up with much higher blood toxin levels than what people are normally subjected to, which may have any number of life-shortening effects.
Sudden adult onset Calorie Restriction shortens the lifespans of mice.
Though the lifespan enhancing effects of calorie restriction have been known since the 1930s, it was also known that if adult mice were suddenly put on a calorie restricted diet, their lifespans were actually shortened.
Dr. Walford found in the 1980s, however, that if mice were slowly transitioned from an ad lib to a calorie restricted diet, then their lifespans increased. The time for this transition recommended by Dr. Walford is a minimum of 6 to 9 months, but preferably 1 to 2 years. [p. 78, BY120YD]