I stumbled across this article about a carbohydrate-restriction study while looking for something else.

British researchers took 88 women considered at high risk for breast cancer and divided them into three diet groups. One group adopted a Mediterranean-type diet with a limit of 1500 calories per day.  The second group was told to restrict carbohydrates to below 50 grams two days per week, then eat normally on the other days.  The third group was also told to restrict carbohydrates to below 50 grams two days per week, but also to limit calories to 650 on those two days.

Here were the results, according to the article:

At the end of four weeks women in both of the intermittent dieting groups had lost more weight — about 9 pounds — than the women who ate low calorie meals every day of the week — about 5 pounds.

Women in the intermittent dieting groups also had better improvement than daily dieters in the levels of hormones — insulin and leptin — that have been linked with breast cancer risk.

Notice that the women who restricted calories every day lost the least amount of weight on average.  I couldn’t find a full paper on this study – the article mentions a presentation, so maybe there is no full study published – so we don’t know if they measured changes in metabolism.  We also don’t know if the women who went low-carb twice per week reduced their calorie intake spontaneously.  All we know is that the women who restricted calories every day lost less weight than those who merely restricted carbohydrates two days per week.

I also found it interesting that both groups of women who restricted carbohydrates lost about the same amount of weight, even though one group restricted calories to 650 two days per week and the other group didn’t.  We’ve seen this happen in several studies now:  people who restrict carbohydrates lose as much or more weight than people who restrict calories, even though the low-carbers don’t restrict calories and are told to eat to satiety.

If you restrict calories enough and can endure being perpetually hungry, you will lose weight.  Nobody disputes that.  But there’s a good chance you’ll also end up with a slower metabolism and be miserable much of the time.  No thanks.  Not when can I keep my weight down just by avoiding sugar and limiting starch.  I’m never miserable while eating bacon, steaks, ribs, shrimp, chicken, eggs and butter.

I know what I ate today (scrambled ham and eggs with onions and cheese for breakfast, Italian sausages and mashed cauliflower loaded with butter and sour cream for dinner), but I don’t know how many calories I consumed today … or yesterday, or the day before, or the day before, or on any day in recent memory.  And I like it that way.

33 Responses to “Intermittent Low-Carb Study”
  1. Kim Øyhus says:

    Genetically modified crops can explain why your health methods work,
    such as avoiding carbs helps avoid wheat containing insect poison making guts leak, etc.

    This movie is quite scientific, and its hypotheses quite interesting:

  2. Stipetic says:

    I don’t have access to this paper, but the abstract is published on Pubmed (with a link to the full): http://www.ncbi.nlm.nih.gov/pubmed?term=Harvie%20Obeisity%202011

    Again, LCHF comes out ahead (and this time it was pitted against a worthy opponent: the mighty Mediterranean diet, rather than the puny AMA/ADA diet).

  3. JEY says:

    Every December there will be a flurry of breast cancer related stories coming from the annual conference held in San Antonio, this was one from last year. Of the hundreds of studies submitted each year, the media seems to run with just a few, sometimes those with questionable science. Of course, my first response was why not restrict carbs everyday to reduce insulin and cancer risk? But a step in the right direction, and this British breast cancer foundation has continued to promote its diet for prevention. Link to more on the trial and their diet. The book has sold out but will be republished next spring.
    My oncologist thought this study of interest and fully supports my ketogenic Paleo diet for its possible cancer recurrence prevention.

    Interesting cause-or-effect question: does losing weight reduce the odds of breast cancer by itself, or does reducing fasting glucose and fasting insulin reduce the odds of breast cancer while also promoting weight loss?

  4. Bong Kim says:

    If you are adapted to low-carb diet, intermittent fasting is easy because you are not hungry that much anyway. I believe intermittent fasting is also paleo just in case our ancestors failed to hunt game in time and they didn’t have a refrigerator.

    Agreed. I go 24 hours without eating now and then. I don’t get the shakes, don’t even get particularly hungry.

  5. Lucy says:

    Counting calories suck. Period.

  6. b-nasty says:

    This seems to support a theory I’ve been kicking around for a while. On a LC diet (especially if cal restricted), it’s probably not a bad thing to have the occasional (weekly/biweekly) ‘refeed’ day where caloric consumption increases a few hundred over maintenance levels. This refeed doesn’t have to (and probably shouldn’t) be a slam of carbs, but should just be enough food to convince your metabolism that you aren’t in a period of famine.

    From a armchair-evolutionist perspective, this probably mirrors the feast/famine feeding pattern of hunter gatherers, who ate a surplus if successful, lower if not.

    I believe that would depend on what issues the dieter is attempting to address. For those who’ve found they need to stay in ketosis to avoid gaining weight, a once-per-week refeed that’s higher in carbs would kick them out of ketosis. I usually have a high-calorie (but not high-carb) day on the weekend for exactly the reason you stated; I want to avoid having my body believe it needs to slow my metabolism.

  7. Liz says:

    I agree about counting calories, but I do feel if I eat primal and am not careful about how much I’m eating, I don’t lose weight, and often I’ll gain!

    I was reading Mark’s Daily Apple a few weeks ago, and lots of women reported not having too much success with IF. You know it’s funny, when I was 20 lbs heavier, restricting calories and IF worked, even if I wasn’t low carb. Now that I’m LC, IF doesn’t seem to work on me at all. I guess we’re all a little different, ehh?

    Sure, we’re all different and there’s no one best diet for everyone. I suspect the intermittent fasting may work for some people because fasting automatically reduces insulin. If you’re strict about being low-carb, insulin would already be down quite a bit, so fasting wouldn’t change that very much.

  8. Marilyn says:

    Tom wrote: “. . .I know what I ate today (scrambled ham and eggs with onions and cheese for breakfast, Italian sausages and mashed cauliflower loaded with butter and sour cream for dinner). . .”

    Question: Did you not eat lunch?

    Often I don’t. I rarely wake up hungry, so by the time I’ve had some coffee with cream in it, I’m good until lunch … er, technically breakfast since it’s the first meal of the day. So I have breakfast around noon and dinner around 6:00. If I stay up late to work or watch something on TV, I’ll have a snack.

  9. Tom, re your JEY comment, It’s definitely the latter since a person can lose weight while still eating a high carb diet via calorie restriction. Immune system strength is a critical part of cancer prevention, so keeping carb intake low to keep insulin and total blood glucose low all the time is a key part to cancer prevention.

    From http://goo.gl/eL0Q9 : “Carbohydrates Lower Immune System was Known as early as 1977, The “Carbohydrates are good for your health” Myth.

    That’s right! Carbohydrates suppress the activity of your immune system. Analyzing blood drawn from subjects, white cell activity was measured before and after various doses of carbohydrates (sugar): 6, 12, 18, and 24 teaspoons worth. The average American consumes at least 70-100 teaspoons of sugar equivalents (carbohydrates) a day, often consuming over 20 teaspoons of sugar at a single meal. DECREASED white blood cell activity was directly correlated with carbohydrate consumption. The group consuming the 24 teaspoons had virtually complete immobilization of white blood cells within an hour after eating. The immunosuppression occurred for up to two hours with adverse effects of blood cell activity continued for up to five hours.

    Carbohydrates cause our bodies many other stresses that all affect our overall well-being: increased fat storage (leading to obesity and all the illnesses related to that); an increase in insulin excretion which causes the adrenal glands to overproduce testosterones which can wreak havoc with women’s natural hormone cycle); blood clotting (leading to blocked arteries and heart disease); decrease in growth hormone (bad!); an instability in mood (the opposite of our belief that sugars give us a “feel good” stability) and more!

    What does this mean in real life terms? It means that following the popular nutritional advice to eat 5-6 times a day with a carbohydrate-based diet can cause IMMENSE DESTRUCTION to your immune system and if you cannot afford to treat your family illnesses, do you really want to take those chances?!?”

    Also see the chart showing the depressive effect of 6 different sugars on leukocyte activity and levels here: http://goo.gl/c23Qt

    I also read (sorry, don’t remember where) that whenever your blood sugar is over 125, you stop absorbing vitamin C.

  10. johnny says:

    How many more studies like this will it take to shut up the high carb/low fat banshees?

    My guess is only a few hundred more.

  11. Peggy Holloway says:

    I’ve had a crazy schedule this past month which has involved teaching voice from 9:00 to 5:00 with no break, driving to a church to direct a choir, then returning the university to do a two-hour coaching session with a student preparing a challenging recital. Voice coaching is actually semi-aerobic – not at all a sedentary job. I have been eating 2 scrambled eggs and some salt pork for breakfast, and then have not eaten all day with this hectic schedule. At 11:00 when I get home, I feel fine; not hungry and still full of energy.
    I have not counted calories in the 13 years I’ve been low-carb and frankly, don’t care how much I weigh either. I’m pleased with the way I look, how my clothes fit, and the fact that I’ve cycled 3000 miles since May (including a one-day century ride) and, at age 60, can keep up the kind of schedule I describe with more stamina/energy than the college students 1/3 my age!

  12. Peggy Holloway says:

    Correction to previous post – I don’t do that every day. 🙂 That is my normal Thursday; other days are similar, but not quite that crazy.

    Whew … I was going to say that low-carb or not, sounds like you need a break.

  13. CJ says:

    This has nothing to do with your post but can you eat pizza on low carb diets?

    Only if you skip the crust.

  14. rob says:

    Nothing new in this study, a lowish carb diet focused on real food is gonna generally be very satiating and make someone unconsciously eat less.

    Water/glycogen depletion can account for the extra weight loss or the LC groups were spontaneously eating even less than the low cal group. It’s common to lose a few pounds or more when one restricts carbs and the scale isn’t gonna make a distinction between water, fat and muscle loss.

    It seems unlikely to me that the low-carb women would be depleting glycogen more rapidly than the low-cal women since they were only low-carb two days out of seven. It does seem likely they dropped their intake, even without a calorie limit.

  15. Clyde says:

    My variation on intermittent fasting is to keep my daily eating window to a 5 hour period (1:00pm-6:00pm). I found I was eating breakfast more out of habit than out of bodily need, so that’s been easy to skip. Nighttime cravings are eliminated by making sure I fill up with lots of delicious animal meat & fats, good oils and yummy veggies. A good night’s sleep takes care of the rest of the time. Easy peasy.

    I’ve done that as well and found it pretty easy to follow.

  16. Bret says:

    (Said Rob) “Water/glycogen depletion can account for the extra weight loss or the LC groups were spontaneously eating even less than the low cal group.”

    The body certainly loses water weight when first reducing carbs. And spontaneous calorie reduction with full satiety is, from what I can tell, more common than not with low-carb eating. The satiety is critical, of course, because it enables long-term adherence to the diet, whereas diets relying on will power to overcome hunger signals have an abysmal rate of failure.

    And still, a lot of people would credit the calorie reduction with the fat loss for the low-carbers (assuming not all of the weight lost was water, glycogen, or muscle–the latter being very unlikely unless protein was reduced as well, which would be an unacceptable confounding variable in an experiment like this). As Gary Taubes would argue, the causality is not owed to the caloric reduction, since that part was done unintentionally and as a direct result of the hormonal changes brought on by the carb reduction. In other words, you could not sustain fewer calories on a higher-carb diet without relying on will power to repress hunger, so you can’t conclude from this experiment that calorie restriction is an effective strategy. If the low-carb diet was required to enable the person to reduce calories without hunger, then the low-carb approach is the causal factor in the fat loss.

  17. Marilyn says:

    This would have been more on-topic a few posts ago, but I thought you’d be interested:


    Granted, it was the Barbie-size portions of garlic toast that caused the most consternation, but the students are noticing the changes, and they are not pleased.

    Nor should they be.

  18. Firebird says:

    You COULD probably have a slice of pizza if you’re monitoring your daily carb count, and if you’re at your allotment, don’t eat carbs the rest of the day. I worry about the grains in the dough, though.

    After reading “Wheat Belly,” I skip the wheat crust even if eating a bit of it wouldn’t result in a high carb count for the day.

  19. Liz says:

    Tom, good point about LC keeping blood sugar low and fasting!

  20. Galina L. says:

    Tom, I also eat egg-based breakfast at 12, sometimes 2 pm, and dinner with my husband at 6. Very convenient.

    It used to be a complete separation between LC discussions on internet and the real life , but even among virtual people around me I started to notice some changes. In the space of two weeks I visited 2 doctors for an annual check-ups. Both my GP and ob/gyn nurse-practitioner mentioned that they now read LC nutritional blogs (I don’t know which ones), a nurse even told me she started to recommend LCarbing to ladies with bothersome menopausal symptoms. My GP put in my file that I follow a LC diet for last 5 years as a part of my medical history. There are also couple people who followed my example and got great results.

    That’s an excellent sign of progress.

  21. Mark says:

    Hey Tom,

    Just wanted to say thanks for making your movie. I had been leaning toward HFLC for awhile now. Your movie gave me the kick to do some indepth research a few weeks ago. Now I’m a full convert.

    BTW, how do you like Tennessee? I live in the Tri-cities area the last 3 years. I love it out here.

    I love it here, especially now that we’re living on almost 6 acres. Peaceful, lovely scenery, nice people, only 10 minutes from downtown Franklin.

  22. Linda says:

    Follow up to Galina L

    I was visiting my opthamologist on Monday, and after the eye exam, during some chit chat, he asked if I had any other concerns or questions and I asked, [just being a smart ass,] how to drop the last 10 pounds I was still carrying. Without hesitation he said, “Follow a good healthy low carb diet.”
    I nearly fell out of my chair!

    There’s hope for humanity.

  23. DrB says:

    RE: pizza on LCHF, Tom (or anyone), have you tried pizzas with crusts made of ‘riced’ cauliflower or cream cheese?

    I haven’t tried either yet.

  24. Terry H says:

    Greetings All:

    Sorry to but in here, but I thought i wd. ask if anyone deals with Paleo-oriented diets and T1 Diabetes. I read a bit and try to filter things thru that perspective as I attempt to apply. Anyone here that cd. lead me to sources concerning, or maybe personal experience wd. be much appreciated. I enjoyed the presentation esp. when the role of insulin was discussed and re-listen every now and then. My apologies if I violated protocol with this post.

    Dr. Richard Bernstein is a type I diabetic. His book may be useful to you:


  25. Sabine says:

    Glad to see a study concerning woman and low-carb. Do you know if the 650 cal group was encouraged to have it as one meal, or spread out?

    The article only mentioned it as a daily limit, so I don’t know.

  26. Raina says:

    Dr B — I’ve made it several times and it’s really quite good. It doesn’t taste like cauliflower at all and gets nice and crispy (can even hold it in my hands like a real crust!)

    I enjoyed it, but am going to try an almond flour one next. Mainly because I keep replacing EVERYTHING with cauliflower (rice, pasta in a casserole, potatoes), so I’m looking for something a little different.

  27. Monica says:

    I saw your movie last night and really enjoyed it. I’m a 20+ year vegetarian (wait, hold your fire for a minute!) who has gotten fatter and fatter. I’ve begun to notice that most vegetarians I know are fatty fattersons too. After all, potato chips, pasta and ice cream are vegetarian foods. A couple of months ago I cut sugar and starches from my diet and the weight started coming off pretty easily. Then a month ago I started intermittent fasting via the Johnson Up Day Down Day Diet and wow, the difference in everything from weight loss, energy level, moods, skin health, hunger satiety and so much more is astounding. I do a modified fast of 18 hours, 3 days a week. When I break the fast in the evening on those days, I eat 500 calories or less of mostly fat, vegetables and some vegetable protein. The interesting thing is I don’t even feel hungry on the down days now and I credit that to the lack of sugar and starch.

    I’m realizing that a meat-eating diet is probably healthier but I just can’t bring myself to eat it so I’ll have to make do with eggs and whole dairy. However, as I learn more about the importance of an abundance of high quality fat, I don’t feel the lack of animal protein is too much of a hindrance. Anyway, thanks for an entertaining and informative film about all this. It’s an uphill battle and you’re doing great work. I will recommend it to everyone I know, especially other vegetarians who’ve bought into the ‘healthier vegetarian’ propaganda.

    The vegetarians I’ve met who are lean and healthy don’t eat sugar or white flour. I think that’s much of the battle right there, whether you eat meat or not.

  28. Sienna says:

    I’ve been following The Wheat Belly diet for about a month or 6 weeks now and have been feeling great, with lots of energy, and have also lost a little bit of flab (yay!). I’ve been telling everyone, who will listen about the book, because I think it’s so interesting, convincing and sensible.

    But as a Dutch baker’s daughter, I grew up eating a lot of delicious bread. We practically lived on the stuff, usually smothered in Gouda cheese and ham. Nothing tastes better, nor is more comforting to the soul, as it reminds me of my childhood, and my parents, who both died years ago.

    I miss my bread so much, that yesterday, while sitting outside on the patio at a local pub enjoying the sunny river view, and my ice cold beer, I indulged in a side of fries and several pieces of roasted garlic goat cheese pizza. The taste was divine, almost orgasmic. And I figured it was harmless to “go off the wagon” for one meal.

    Man was I wrong. I was awake almost all night with gas, bloating and an ache in my guts that still hasn’t gone away, nor has the headache or lethargy. Was it the crust, the cheese, the beer or all 3 I wonder? I dug myself into a deep hole and it’ll take a while to get out. It’ll be a salad and some chicken breast for supper I guess. Fasting would probably be advisable don’t you think? 🙂

    BTW both my parents had diabetes when they got older, and 3 of my older brothers have it too. I’m trying to follow this diet so I won’t be a victim.

  29. Julie says:

    Thanks, Tom! Been HF/LC for only a few weeks, and have been worried about those days where I just don’t feel like eating (afraid that I’d slow down my metabolism). Nice to know it’s pretty normal instead of trying to stuff myself on those days I feel averse to the food.

    Just let your appetite be your guide. It’s pointless to eat when you don’t feel like eating.

  30. Jake says:

    I’m a heavy milk drinker and have followed 2 diets all my life. I eat completely based on mood and I’m usually one to eat a lot (2000 or so calories most days). I had noticed when I was eating more meat, dairy, and fruit, I was generally less depressed, happier, and later on found out it helped with my ADD. But then I’m also a light-weight and with my decent metabolism it’s always been hard to gain weight without gorging on heavy carbs, and I do gain weight usually, but I feel weak and agitated and such.

    I found a website that advocated a heavy protein/fat diet for ADD people and continued to see that connection. Now a few years later, I run into your documentary and it restates everything I’ve previously learned about sat fats and how I feel better when I eat “real food.” I’m so glad to have found your documentary and have been telling others about it!

    One question though, the paleo style diet seems to be against drinking milk, and I both enjoy it and drink it at 9/10 meals. Is this something that is more individual for tolerance?

    Yes, it’s a matter of individual tolerance. Milk is a fairly new addition to the human diet and many people have negative reactions to dairy foods.

  31. Julie says:

    I went fully low carb last week (including eating meat, which I haven’t done in fourteen years), and I noticed something very interesting. Back when I was following a low calorie diet, I tried to eat about 1700 calories, but it was miserable and I was hungry all the time. But with a low carb diet, I actually eat 1700 calories naturally! Even with the butter and heavy cream and bacon, I don’t eat any more than I used to on a low calorie diet, except now I’m satisfied and never hungry. It’s only when I start eating sugar and grains that I get hungry. I just wish everyone knew about this.

    That’s a big part of why low-carb diets work.

  32. low carb is waaaay better than low calorie. Julie is right when she says she can eat more on a low carb diet when compared to low calorie. After 3 months on low carb it became so natural i switched over to a ketosis diet. Keto was a little harder, but the weight loss felt faster with less effort.

  33. Jeannine says:

    Ok if I eat window between 745am till 1145am stop eat noon start fasting till 8am on next day love low carb high fat with fat bomb everyday let me know ok if it still burn fat and build muscles. Thanks need lose 10lbs

    Just make sure you get enough protein to maintain muscle.

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