Calorie Restriction – The Quality of Diet Seems to Matter


This man starved eating a high carbohydrate diet consisting of 1570 calories a day.

While I was reviewing the research available on intermittent fasting I came upon an article on Tim Ferriss’ website about the science of fat loss and the “calorie is a calorie” myth. He invited Dr. Eades (author of Protein Power who has worked for 2 decades on low-carb dieting) to take the stage and compare two studies on diet which employed vastly different methods and produced vastly different results. I thought those results were telling on the issue of calorie restriction.

The first study, a 1944 Ancel Keys study, severely restricted calories in 36 men in order to observe the effects of starvation. He fed his subjects a restricted calorie, high carbohydrate diet for twenty four weeks. The macro-nutrient breakdown looked like this: 25.5% protein, 17.2% fat and 57.3% carbohydrate. The subjects demonstrated lethargy, depression, feeling cold, bleeding disorders, swollen ankles, food obsession, and other more serious psychological disorders. (You can read about the study in detail in the book The Great Starvation Experiment.)

The second study, a John Yudkin study, attempted to show that a low carb diet provided ample nutrients. The carbohydrates were kept strict each day but subjects were asked to eat “as much meat, fish, eggs, cheese, butter, margarine, cream and leafy vegetables as they wished.” Their average macro-nutrient profile looked like this: 21.3% protein, 60.6% fat and 17.1% carbohydrate. The 11 subjects in the John Yudkin study volitionally consumed the same number of calories as those in the Ancel Keys study, but the calories came from totally different sources. No symptoms of starvation were reported and, in fact,

“none of our subjects complained of hunger or any other ill effects; on the other hand, several volunteered statements to the effect that they had an increased feeling of well-being and decreased lassitude.”

The effects of “calorie restriction” in these two studies are startlingly disparate. Eating the same number of calories one group starved while the other thrived.

Is it just calorie deprivation that causes starvation (obviously true at some point) or is the quality of food to blame?

Dr. Eades discovered, while comparing the results, that the calorie restricted, low-fat subjects were lacking cholesterol and saturated fats which we know contribute to elevated mood. According to Chris Kresser (and like everyone else that has woken up),

“Cholesterol is needed for proper function of serotonin receptors in the brain; low cholesterol levels have been linked to aggressive and violent behavior, depression and suicidal tendencies.”

It seems that calorie restriction is being tossed around as a bad thing based on a handful of studies done on humans and rats eating foods that they were not designed to eat in the first place. These studies supposedly offer “proof” that calorie restriction causes everything from bone loss, anxiety, irritability, to hostility.

I might be totally missing something here and I realize the John Yudkin study was one small study, but it is perfectly in line with my own experience. My calories are restricted in general – I just don’t think about eating all that much and don’t usually eat huge meals – and I am not irritable, angry, bleeding, or swollen and, in fact, am quite calm and easy-tempered. Is this not true for most of us Primal people?

Unless I am mistaken, these studies are bunk, as are most studies researching nutrition based on the Standard  American Diet. Until I see some calorie restriction studies done on subjects eating more like me, I’m not going to pay any head to the warnings against it.

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  1. I totally agree with this. Before I started eating Paleo, I tried to stay around 1500 cals a day. I was always hungry, and felt like I was depriving myself from eating. Since I started eating Paleo, I eat whenever I am hungry, and I notice that most days I don’t even reach 1500 cals just because I am not hungry. I love eating healthy, and not feeling hungry all the time.

    My name is Katie by the way! I have been reading your blog recently when my sister and I decided to go Paleo. I went gluten free in January when I found out that I was intolerant, and since then have read more and decided to go all the way Paleo. I am definitely still learning how to eat it’s nice reading other people’s blogs to learn more.

    • It has been much easier for me to transition to Paleo/Primal knowing that I’m gluten intolerant. If it had not been for this diet, I may have never found that out (the blood tests didn’t show anything). If you are going to cut out wheat, you might as well cut out all grains. Plus when people try to push cookies on me or something I can just say I’m allergic. :)

  2. Hi Katie. Welcome! I am really aware too of how many calories I consume because I myself am a recovered a calorie counter. It’s a skill you never really lose. So now-a-days, I have an idea of my calorie intake – even though it doesn’t matter – and know that it is much less than what I used to eat back when I deliberately restricted calories and always felt hungry!

  3. I agree with Katie (both of you!). I have a very good idea of how many calories I eat each day and it’s probably around 1500-1700… but before I started eating a more paleo diet I was susceptible to binges and being obsessed with food… Now I just enjoy eating :) and my friends are jealous because it looks like I’m eating “crap” (bacon! Yum!) but I’m still thin. I have had issues with my period and I’m hoping paleo will help get my hormones back on track (I’ve only been paleo for a few weeks… I was leaning towards it before but couldn’t seem to give up my sugar addiction). Ayway I’m very glad I found your blog the other day! Great post! I had read about the minnesota study but didn’t realize it was high carb.

  4. Dude, eating only 1500 calories of anything per day would make me a sad panda.

    That being said, I have totally noticed a general decrease in between-mealtime hunger. And I am now able to occasionally skip breakfast (a little trial IF).

    Of course when it’s time to eat, let’s feast!

    I think it’s important to note that it’s critical that you already be in pretty good shape when starting to look into IF. IF is not for someone losing a bunch of weight or someone that is suffering the effects of Metabolic Syndrome (such as diabetes) without the consultation of a doctor or nutritionist, as it can have serious adverse effects on the immediate health and wellbeing of the individual. The same is true of a Tim Ferriss style binge.

    However, for someone who is healthy and has already established a clean method of fueling I think that IF is definitely something that could be looked at and considered as part of a comprehensive health and wellness regime.

  5. Hal,

    Just because subjects in that study ate 1500 calories doesn’t mean I think you should too! That is pretty low, indeed, but at least if you ever have to, it appears as though it won’t kill you or cause you too much mental strife, assuming you keep your fat and nutrient intake high. Anyway, not suggesting you give it a try!

    You might be right about being in good health before getting started with IF. I brought attention to that in the Intermittent Fasting article. However, it’s interesting to note the reactions of people who actually tried it soon after switching over. Experiences really vary from person to person (read about it in forums to see what I mean). Some people claim that IF actually was the final key to their recovery. Others claim that it messed up their blood sugar. Proceed with caution!


    I have faith your hormones will balance out. Mine did, as have the hormones of countless other women in the community. It’s a REALLY common disorder among women, and getting back to the basics is just about all we need. I wish you the best of luck in kicking that sugar addiction. Keep eating your bacon and being the envy of all your friends!


    Sometimes I think gluten intolerance was my saving grace. It dragged me down so unbelievably far that I was more compelled than others to find a way out and now I’m so much healthier for it. Plus it does make it easy to turn down food! People don’t question my motives as much.

  6. Interesting post. I’m currently reading Taubes’ “Why We Get Fat” which talks about the calories in v. calories out theory. It’s amazing how many studies there are to support the paleo/primal lifestyle, yet followers of CW cling to that on blind faith and ignore the facts.

    A note about intermittent fasting; I’ve found since I went 100% primal, I am unintentionally IF’ing about 16hrs a day. I’m simply not hungry much of the time, and it feels fantastic to not be preoccupied by food!

  7. So, if what I’ve gathered is correct, it’s not the end of the world if you’re a moderately active person that’s only eating 15-1700 kcals/day? Recently I was curious (tho I’m 5 months pregnant, so I spose I’m not the norm) about whether my weight gain was normal or if I was gaining quickly so I counted my calories for about a week.. Seems as tho I was averaging right around 1700, once was 15-smthn and another was 16-smthn, there were a couple 18-smthn days.. I was initially worried that I wasn’t eating ENOUGH, but I didn’t really have any desire to eat more, atleast nothing more that fits into paleo/primal (sugary stuff, yeah, but that’s something I’ve cut out, so the desire doesn’t count!)

    Just curious.. I know you’re not a doctor and whatnot, just curious if I interpreted this the same way as others.. or if my experience matches up with others. I figure if I’m not hungry, there’s no reason to eat anyways just to have a number that fits in what’s thought to be normal, but you never know.. pregnancy messes with you :)

  8. Heather,

    Isn’t the freedom a great relief?!!


    Unless you have some kind of eating disorder then you should only need to eat when you are hungry. However, a low carb diet can suppress appetite. In this case you may want to force a bit more food down or eat some carbs to increase appetite.

    I was paleo too when I was pregnant, and I only ate when I was hungry – not according to some schedule. I felt plenty satisfied but my calories were well below 2000. There is no definitive guide to how many calories pregnant women should eat. They should eat good primal food when they’re hungry. That’s all.

    • Nope, no eating disorder! :) Glad to know that I’m not the only one.. I’ve looked around for calorie requirements and such, but all I see indicates that I should eat practically 3000/day, and that seems insane, atleast on a regular, sustained basis..

      Will take into consideration the low-carb/appetite suppression, but I still eat a decent amount of potatoes, have seen many mixed reviews on them and haven’t personally found any issues with them.. I also cut out dairy for a good month or two, but when bringing Kefir/butter/cheese back in, didn’t experience any problems at all, so it’s not like I have an extreme diet in that respect.. :)

      Thanks for the response and advice! :)

  9. Those studies are fascinating. “25.5% protein, 17.2% fat and 57.3% carbohydrate” sounds rather similar to the USDA’s recommendations. It’s like maybe we really have need for a certain amount of protein and fat, and carbs are just a filler…and if we have too much filler and too little of the necessary stuff, we are going to be deficient. This would explain why dieting often leads to hunger and crankiness. And why people who eat a higher percentage of carbohydrates are fatter–they have to eat more in order to get their allotment of protein and fat.

    I’ve also read that people who consume fewer calories live longer…I’m going to go out on a limb here and guess they are probably eating a lower carb diet.

    Thanks for sharing!

  10. Peggy-

    Great blog! I’m here because I saw your reply to Mark Sisson’s page. I found Mark Sisson by accident actually. Always the dieter, I actually entered “how many carbs do you need to eat in a day” and there he was! The irony of the situation is that after completing a P90X workout, there was Mark Sisson talking about the Results and Recovery drink at the end of the video! Weird! So I went back to his blog and really started to dig into what he was saying and well- I am not 100% paleo just yet – I am eons from where I started. I still like to exercise but I don’t want to have to kill myself every day for the rest of my life. Who does? well some people apparently. Anyway – I digress

    There is a point to this! While messing around on the internet I found a blog called 180degreehealth. He called Mark Sisson ” the laughingstock of anyone who studies obesity or nutritional science. He completely undermines his credibility as an intelligent person with this one uber-knuckleheaded and poorly-thought out conclusion. ”

    He went on to say some utterly ridiculous statements to the effect that he consumes >300 grams of carbs before noon. I stopped thinking. I immediately went to the nutrition book and realized that 300 grms of carbs is equivalent to 4 pounds of pasta. How could ANYONE eat that much?? He and I went back and forth and he was pleasant as explained that he eats 3000-3500 calories a day – mostly fruit and fruit juice. I explained that I’d have to go out of my way to eat more than 150 grams of carbs a day – which then prompted him to call me “metabolically crippled” and a tree sloth. Charming dude huh? He also said that I should go out of my way because a study showed that when caloric intake was doubled the group lost 67% of their body weight over 1 year. What he didn’t mention is that the study was on apes in a zoo and that the zoo vets swapped out the sugary food they had been feeding them and replaced it with protein.

    Still getting to the point – I promise. What he didn’t want to hear is that I am not hungry. I don’t NEED to eat more than 1200-1700 calories a day (I have hungry days and not so hungry days – doesn’t everyone?) and I don’t feel like I am depriving myself. I don’t jones for bread anymore- or SUGAR in general. 3 years ago I lived on bagels, sweet tarts with a salad thrown in for good measure (because I do legitimately love veggies and I craved them ).

    Anyway – that was a long story but it amazes me that this guy has 100,000 followers. He is a total hack and irresponsible..

  11. Okay. I have another question because I just got on the scale today and I’m down to 118 lbs. This is scaring me. Before I was diagnosed with celiac disease, I weighed 175 ish lbs. I’m 5’3. I couldn’t lose weight for the life of me. First I went off gluten and dropped about 40 lbs. I felt better, but still had major problems. I dropped dairy except ensure and dropped about 10. Now that I’m trying to go primal/paleo, the scale is dropping and I’m really just a slave to Western diet propaganda. Is this dangerous? I don’t want to waste away to nothing, but I’m just not hungry and I don’t eat when I’m not hungry. I can’t eat grains at all anymore because they just kill me. What can I do to maintain or gain weight as a paleo/primal eater?

    • I know the feeling. When I eat zero carb I tend to have very little appetite. But then I don’t eat fiber either so there’s not much there to stimulate appetite. These days I don’t do zero carb. I still keep my carbohydrates low in general but the lack of appetite on zero carb can easily turn into starvation for me. Eating zero carb can also cause glucose deficiency. If you aren’t eating enough carbs to supply your brain’s need for glucose and say you’re only barely eating enough protein, then your muscles will suffer because the brain gets first dibs. Try adding a little carbs if you’re not eating any and see if that improves your appetite. Which type of carbs you eat is up to your body. Personally, I cannot eat starch or fruit. Both of them make me feel horrible. But table sugar works just fine for me. I have a little bit of sugar with meals. I know that the Paleo community despises sugar, but you do what you have to do. My digestion and temper and everything else is ruined by starches, so it’s a little sugar or zero carb.

      • Isnt there a process called glucogenosis where the body converts fat into glucose which means you dont actually need carbs to fuel the body or the brain.

        • sorry i meant gluconeogenesis

        • Yes there is. Though whether that is the most efficient metabolism for a human is unknown and much disputed. Just because our bodies are able to do it doesn’t mean that they always should.

  12. Hi, I recently found your blog and it is so interesting. Your story is different from any I’ve heard before.
    I’m well versed on the Minnesota starvation experiment, as it is often used to explain what happens when one suffers from an eating disorder. I have suffered for years from anorexia and bulimia. I am currently “recovered” although still plagued by destructive thought patterns and poor body image. I also have a lot of lingering health and hormonal issues. I’m not paleo but transitioning to that style of eating to see if it helps. However, I’ve been told by eating disorder specialists that calorie restriction is the enemy and that it will lead to a lot of health problems and most probably a relapse for me. My plan is to try paleo without any caloric restriction, even if I’m not hungry, although now I’m wondering if it is detrimental to eat more than one is hungry for. It is very difficult to dig through the conflicting information and find out what is actually true (or perhaps there are no universal truths and everyone is completely different). Anyway, thanks for this perspective.

    • Ryan, your situation may be a little different. I think it’s ideal to follow your body’s cues but your cues may be off or you may not perceive them correctly after years of eating disorders.

      You could shoot for 3, 4, or more meals a day (following your doctor’s recommendations) just to get yourself back on track and then eventually allow yourself to listen to your body’s hunger cues, if it doesn’t cause a relapse.

      Eating a little more than you need each day isn’t going to cause any health problems. Humans and other animals do this when food is abundant.

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