Calorie restriction and longevity [closed]

Question

I'm interested in the known (at least informally) correlation between calorie restriction and longevity, a fact known in other organisms.

There's some detail that I don't understand. How can someone be in calorie restriction in the long-term?, something makes no sense to me.

I guess it's an stupid question, but I really don't get it.

Answer 1

It's implied that 'calorie restricting' is ingesting no more than is needed to maintain daily activities. Of course, if you have some reserves when you start the practice you can intake many fewer calories than you burn. But, you're right, eventually you'll need to start measuring out your food to match your burn. Many aggressive practitioners are very detail oriented in these counts and estimates of calorie burn.

Answer 2

The most straightforward way to restrict calories in the long term is to just continually undereat. It you don't overdo it, it will just make you weak and miserable, not dead.

However, it may not be necessary to actually do that. Intermittent fasting may give you the benefits of caloric restriction without actually starving you. Studies have shown alternate day calorie restriction (ADCR) to be quite effective, I'm not sure if there is hard data on other forms of (intermittent) fasting.

One possible mechanism as to why calorie restriction promotes longevity is that deficiency in essential amino acids triggers autophagy, a process by which cells recycle parts of themselves. Never being hungry may mean your body never cleans house, and crap like misfolded proteins just accumulate.

The easiest way to induce this may be to restrict protein temporarily. Try to temporarily get no more than 5% of you caloric intake from protein. Wheat as a protein-source is quite handy here, as it is low in protein to begin with, and especially low in lysine, so eating a little wheat will leave you deficient in lysine.

Tim Ferriss suggest a "protein cycling diet" as described by Ron Mignery in his book: http://knol.google.com/k/ron-mignery/protein-cycling-diet/2s3nmvrwklbxs/1

Protein restriction appears to take at 18 hours to trigger autophagy.

Answer 3

Your body will adapt to the amount of calories/nutrition you give it over time. That means if you give yourself very few calories and a small amount of protein the body will attempt to pull this energy from its existing resources: this means its fat and muscle/organ stores. Additionally, if you overfeed yourself in all categories of food (including protein) your body will respond by storing that excess as fat.

Now, within calorie restriction different studies have shown the effects of restricting certain types of calories vs. others. For example, restricting carbs while maintaining protein is observed to maintain your muscle/organ mass while depleting fat reserves. Obviously restricting all of any major class of foods (proteins, carbs, fats) is going to make your body deficient in some way, typically the types of nutrients that are prevalent in that type of food. Some of our vitamins/minerals come from carbs, others come from fats, and some are found in red meat (like iron).

Essentially your body adapts as best it can. The trick is finding out how to make your body adapt in a way that you want. Nothing should be considered as simple as strict calorie reduction. If you have insufficient calories overall, you will find that recovery from exercise or injury takes longer. If you have a surpluss of calories overall you will gain more fat--even on a 100% protein diet. Some people (like a good friend of mine) have abnormal metabolisms and allergies to certain foods--the rules that work for most people won't work for people with abnormal metabolisms.

Answer 4

A calorie restricted diet for longevity is able to be sustained in the long term because people who follow it select their foods in order to specifically satisfy their nutrient requirements with the least number of calories. The calorie reduced diet for longevity includes High-ORAC foods (Oxygen Radical Absorbance Capacity), Nutrient Dense foods, and Low Energy-Dense foods (high in volume and low in calories). It can be a healthy diet and lifestyle if you are well educated about eating the right foods and proportions, but it can be detrimental if you are not vigilant about getting all your nutrients.