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The Ice Diet

The water content of plant foods may help explain why those eating plant-based diets are, on average, so slim. Can ice be thought of as having even “fewer” calories than water since the body has to warm it up?

August 31, 2012 |
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Supplementary Info

Sources Cited


Thanks to Ray Chronise for patiently walking me through the thermodynamics of ice consumption. Images thanks to Ray, JennaPrete, and cheesy42.


If phytonutrients can alter gut flora in a way that helps people lose weight, then you’d think people eating diets based on plants would have significantly different colon populations and yes indeed, that’s something that been known for four decades, and may help explain why those eating such diets tend to be slimmer.

Another reason vegetarian eating patterns has been tied to better weight management may be the water content of plant foods. Fruits and vegetables average about 80 to 90 percent water. Just as fiber can bulk up the volume of foods without adding calories, so can water. Cognitive experiments have shown that people tend to eat a certain volume of food, and so when that volume is mostly water they don’t end up gaining as much weight. But even if you take out the visual component and instead stick a tube down people’s throats and feed them whatever volumes of food you want, if you add more water to their stomach they tend to eat less, perhaps because of the stretch receptors in their stomach sending signals too the brain saying we’ve had enough… Scientists have identified a multitude of ways your body controls your appetite, and a good thing, because if you’re off every day just by a few percent that could have huge impacts on your weight over the years.

If water is so helpful… why can't you just eat that steak and drink a glass of water. It doesn’t work. You feel more full during the meal, but you end up eating the same number of calories throughout the day, unless, they’ve found, you preload. Drinking water with the meal doesn’t seem to help control calories, but drinking a big glass of water a half hour before a meal might. "Thus it appears that water on its own may be effective at increasing satiety and decreasing intakes for some population groups when drunk before, but not with, a meal.”

Ice water may be even better. Or even, just ice. Water has zero calories, but ice has less than zero since our bodies have to warm it up. From the annals of internal medicine: The ice diet. Using simple thermodynamic calculations of how much heat our body would have to generate to take an ice cube up to body temperature, they conclude eating a quart of ice, like a really really big snow cone--with no syrup--could rob your body of more than 150 calories, the “same amount of energy as the calorie expenditure in running 1 mile.

Sound too good to be true? It is actually, as Ray Crow-nice talks about in his body hacking work with thermogenics, you may just be diverting some of the body's waste heat If one really wants to use chronic mild cold stress to lose weight, turning down one's thermostat or wearing fewer layers outside may be more effective in the long-run than drinking slushies of slush.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

The reference to phytonutrients altering gut flora was an allusion to yesterday's video-of-the-day Tipping Firmicutes to Bacteroidetes. Not only is fiber also calorie-free, but one might think of it in the same snowcone "negative calorie" light, given the fermentation of fiber in our bowel into anti-obesity compounds (as well as anti-inflammatory, anti-cancer compounds). On Monday we'll continue with the obesity prevention theme with Diet vs. Exercise for Weight Loss, one of the videos I featured in my full 2012 presentation Uprooting the Leading Causes of Death.

For some context, please check out my associated blog posts: The Ice Diet and Schoolchildren Should Drink More Water

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Michael Greger M.D.

    The reference to phytonutrients altering gut flora was an allusion to yesterday’s video-of-the-day Tipping the Balance of Firmicutes to Bacteroidetes. Not only is fiber also calorie-free, but one might think of it in the same snowcone “negative calorie” light, given the fermentation of fiber in our bowel into anti-obesity compounds (as well as anti-inflammatory anti-cancer compounds). On Monday we’ll continue with the obesity prevention theme with Diet or Exercise: What’s More Important for Weight Loss?, one of the videos I featured in my full 2012 presentation Uprooting the Leading Causes of Death.

    If you haven’t yet, you can subscribe to my videos for free by clicking here.

    • HemoDynamic, M.D.

      Awwwe.  And I was about to eat steak with ice (see pic below) but this vid saved me from demice (demise)

      • HemoDynamic, M.D.

        You’re as Cold as Ice to me.

  • Ray Cronise

    Thanks Michael!  more info can be found at

  • Luveggies

    A strange hypothesis re: burning calories: 
    Wear a chilled shoulder ice wrap. Hypothetically speaking, by lowering the temperature of brown/”beige” fatty tissue located between our scapulae, one may be able to increase activity of this fatty tissue, which is brownish in color due to a high # of mitochondria. The mitochondria in these fat cells switch into high gear and burn calories to generate heat to help maintain core temperature stability.

    Uhhhh, i’ll just go out for a run instead… 

    • Coacervate

      The first two times i go ice fishing i get chilled, hypothermic and unhappy.  By the third week, I feel excited, my heartbeat throbs in my fingers and toes and I become strangely invincible for many hours on the ice.  its the same every year.  Somehow, exposure turns on the brown fat and then you can litterally jump naked into ice water and like it!

      • Luveggies


  • gary yrag

    I have read that, in longevity studies on mice, a cooler body temperature induced by cooler air temperatures is an independent factor in extended lifespan. This is separate from lower body temperature that results from calorie restriction. Maybe cold drinks would have the same effect? Would make for an interesting study on mice or some other lab animal.

  • Wchiwink

    I’m 55 and stopped eating meat and adopted a plant-based diet when i was 17…..thanks to this site, i’ve even stopped eating small fish, as i really did notice the difference in inflammation, which i suffer from due to back problems….i’m almost vegan but cannot declare myself as one because i still once in a while consume ghee, honey, goat and sheep cheese, and wear wool…
    i am at optimum weight. i do drink water before a meal.
    being (almost) vegan and at optimum weight, i don’t see  the need to drink or eat “ice” to burn calories, as i need all the calories i consume! Chinese medicine and nutrition warn us against eating too hot or too cold…
    Perhaps this “ice diet” would only be beneficial for those who are over-weight!

  • DanielR

    Humans should eat what they are genetically adapted to eat.  Eskimos should eat meat and fat while Indians in the jungle should eat more plant based foods.  But guess what?  The Indians also hunt.  When you compare the SAD American diet to Vegan diets of course people are going to be slimmer.  This isn’t science.  This is picking and choosing information that support a hypothesis rather then looking for evidence that contradicts it.  Sooooo common with so called ‘nutritional science’.  Read Biochemical Individuality by Roger Williams, PhD who by the way discovered pantothenic acid.  Until you start to apply natural selection, geological and biome differences and nutritional anthropology your all going to be like a chicken with your head cut off.  TIME FOR SOME BASIC LOGIC IN MEDICINE AND NUTRITION!!!!!!!!!!!!!!!!!!!!!

    • tanonymus

      You realy think Eskimos are geneticaly adapted to eat meat? How long will it take to adapt to S.A.D.?

  • DanielR

    The Concentration camp diet: people eating air tend to be thinner then people on the Ice Diet!  Man I’m on to something lol.

  • Nina

    Isn’t the reason that drinking water 20-30 minutes before a meal makes you less hungry and less likely to eat as much is because most of the time when you are “hungry” you are actually just dehydrated? Thus when you are dehydrated you think you are hungry because our bodies extract the water out of whatever food we eat. Is this not the reason drinking more water shrinks your waist line?