Calorie Restriction, CRONies and Life extension



“Bon Appetit!”

About 75 years ago Clive McCay, a biochemist and nutrition scientist at Cornell University, noticed that his rodents fed a low calorie diet lived longer. Prof McCay then went on to study ageing, and his (and others) exploration of reduced calorie diets was the birthplace of calorie restriction (CR) for life extension.

Enter the CRON Diet

Calorie Restriction with Optimum Nutrition or CRON is a group of more recent diets that reduce the calories in the diet whilst trying to keep the levels of especially micronutrients high. They’re a development of CR the aim being to avoid diseases caused by inadequate levels of vitamins, minerals and so on.

Practically speaking CORNies, as they’re called, will seek out nutrient dense but calorie sparse foods, for example fibrous vegetables, whole grains etc and they will also use tricks to get the most nutrition with the least energy intake peeling an apple, eating the peel – where most of the micro and phytonutrients are to be found – and throwing away the sugar containing flesh.

So what’s the point?

There’s a growing body of research that shows that reducing calorie loads anywhere from 10 to 50 odd per cent can extend lifespans in a range of animals. Research which is brought together in reviews  like THIS , THIS  and THIS  shows that there’s a physiological basis for hope that this approach can work in humans.

There’s a few holes in the evidence though, one is that the bulk of the research results don’t actually include humans. This is of course due to the difficulties of testing these properly in humans, our lifespans the ethics and structuring of the research. There’s also confounds, for example some diets that are given to lab animals are so poor that actually allowing them to eat less of what really is junk food could be the major factor at play.

CRON in humans

Regardless of the issues with the evidence people are using CRON and their markers of health, things like better body composition and cardiovascular health usually suggest there’s a long term benefit. In a nut shell the evidence can’t say if life is extended but it will help you to stay more healthy in old age.

CRON diets usually shoot for a calorie reduction of about 20-30%, and protein intake is also targeted for reduction due to the issues like mTOR and IGF1, both of which are stimulated by protein intake and that can, it is thought, be a big player in the development of disease, especially some cancers.

The news is not all good and there are drawbacks. CORNies are often skinny, have low much mass and as such strength. Not too much of a problem in today’s world. Many report being constantly cold as well, which is a hassle, but again clothes are available.

In fact the #1 BIG problem is the diet itself.

An example day on the CRON Diet:

1 cup Orange Juice
1 poached Egg
1 slice mixed grain Bread
1 cup brewed Coffee or tea

100g low fat cottage cheese mix with
100g plain non-fat yoghurt +
1 tblsp toasted Wheat Germ
1 Apple
1 whole wheat English muffin

80g Chicken Breast without skin, roasted
1 baked Potato, w/skin
1 cup Spinach steamed


Now that doesn’t look like something that I could sustain for a week, let alone the rest of my life and this is the issue.

And therin lies the rub…

We know that many diets ‘work’ the problem comes when trying to follow them long term. For most the CRON diet is just not sustainable, but there’s another way to get these same types of advantages without having to miss out of the foods you like… Check the DODO Diet for details!

Drew Price is a Registered Nutritionist and the author of The DODO Diet, a practical guide to tailoring intermittent fasting to your needs be it fat loss, better health or lean muscle and performance gains.

  1. I'm available for lectures, book signings, clinical and advisory work. If you have questions about the DoDo Diet please use the comments or social media so everyone can benefit.