Multiple studies have shown that restricting calories can have a positive impact on lifespan and overall health. Yet, most of us find it pretty tough to actually do it. 

In the well-known “Minnesota Starvation Study,” volunteers experienced obsession with food, constant hunger, psychological and emotional challenges, and bingeing. It should give us cause to stop and think when we learn that even the researchers who study the benefits of restricting calories rarely do so themselves. 

We’d all like to know: isn’t there a less psychologically damaging way to extend our lifespan, improve our health and slow our aging? 

Researchers asked the same question, and their search brought them to rapamycin, a substance that blocks TOR (the aging enzyme). Unfortunately, this pill, like most, came with some serious side effects.

The search continued.

The big breakthrough? Researchers realized that test subjects could obtain the same positive results as they had from restricting calories, simply by restricting protein.

Interesting, hey?

Let’s look at the first big, comparative analysis of dietary restrictions. From these results it appears that protein intake has a greater impact on lifespan than calories. What’s more, reducing protein intake, without changing one’s calories at all, seems to offer comparable life and health benefits to those of restricting calories.

And gorgeous, that’s a great thing, because a low-protein, healthy carb diet is exactly what I recommend to you —and I can tell you from experience that this kind of diet is delicious, energizing, and so easy to maintain!

Not only that, this low-protein diet inhibits TOR (those aging enzymes) and IGF-1 (those growth hormones we’ve talked about —which in turn improves health and lengthens lifespan dramatically.

You may be surprised to hear, however, that not all protein was created equal. Some proteins—namely, those derived from animal products—are much, much worse for us. How do we know? A certain amino acid called leucine seems to have the greatest impact on TOR levels. Leucine, incidentally, is found in dairy, all meat, eggs and other animal products. Fruits, veggies, legumes and grains, on the other hand, contain extremely low amounts of it.

To reduce our leucine intake—and thus to improve our lifespan and overall health, if you’re following—we must limit (or ideally stop) our consumption of animal proteins. 

Let me just put this into perspective: to consume the same quantity of leucine that we’d get from a serving of dairy or meat, we’d need to eat 4 large heads of cabbage or 8 dozen apples! Even I can’t eat that much fruit! 

All this could explain why certain groups of people, like the Okinawa Japanese, have such extraordinarily long lives (and youthful appearance). Traditional diets in these cultures consist of just 10% protein, are practically cholesterol-free and more or less plant-based, and consist of less than 1% fish, dairy, meat or eggs. (That’s about one serving of an animal product every month or two.)

So, we’re getting closer to understanding the science behind why plant-based populations live so long…wouldn’t you like to know how it feels, too? Need a little help transitioning to a healthier way of eating? You understand this concept but don’t really know how to implement it into your kitchen? In my latest book (click here >) HEALTHY, SEXY, VEGAN. I show you how to discover the best health of your life as you live and eat in harmony with your body. Check it out now!

For life,




Michael Greger, M.D. FACLM

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UN Das. When less is adequate: Protein and calorie restriction boosts immunity and possibly, longevity–but how and why? Nutrition. 2009 25(9):892 – 895.
R Pallavi, M Giorgio, P G Pelicci. Insights into the beneficial effect of caloric/ dietary restriction for a healthy and prolonged life. Front Physiol. 2012 3:318.
S Davinelli, DC Willcox, G. Scapagnini. Extending healthy ageing: nutrient sensitive pathway and centenarian population. Immun. Ageing. 2012 9:9.