by Marion Nestle
Aug 5 2012

Low carb or low fat: Do calories count?

Here’s my once a month on the first Sunday Food Matters column for the San Francisco Chronicle, out today:

Nutrition and public policy expert Marion Nestle answers readers’ questions in this column written exclusively for The Chronicle. E-mail your questions to, with “Marion Nestle” in the subject line.

Q: I’m confused about calories. If I cut calories to lose weight, does it matter what foods I eat? Or are all calories the same?

A: As the co-author of “Why Calories Count: From Science to Politics,” I hear this question all the time.

The short answer: Calories matter for weight. The choice of foods that provide the calories matters a lot for health and may make it easier for you to diet successfully.

To lose weight, reducing calorie intake below expenditure works every time.

To prove this point, a professor at Kansas State University lost 27 pounds in 10 weeks on the Twinkies diet – one Twinkies every three hours with occasional snacks of chips, sugary cereals and cookies. Even so, he cut his usual calorie intake by 800 a day. Anyone would lose weight doing that.

Only four dietary components provide calories: fat (9 per gram), carbohydrate and protein (4 per gram each) – and alcohol (7 per gram).

Does the particular mix of these components make any difference to weight loss? Yes, say proponents of diets low in carbohydrate, especially rapidly absorbable sugars and refined starches.

Low-carbohydrate diets are necessarily high in fat, and somewhat higher in protein. Do people lose weight on them because of the effects of carbohydrates on insulin levels or because low-carbohydrate diets help reduce calories?

This question does not have an easy answer, but not for lack of trying. Weight-loss studies are hard to do. Estimating calorie intake is notoriously inaccurate, and measuring calories is difficult and expensive.

The first measurement study I know of took place in 1964. Investigators from the Oakland Institute for Medical Research studied weight loss in five obese patients in a hospital metabolic ward. They calculated the number of calories needed to induce rapid weight loss in each patient, and fed each of them a liquid formula diet containing that number every day. Every few weeks, they changed the formula to vary the proportions of protein (ranging from 14 percent to 36 percent of calories), fat (12 percent to 83 percent), and carbohydrate (3 percent to 64 percent).

Regardless of the proportions, all patients lost weight at a constant rate. The investigators titled their study “Calories Do Count.”

This study was conducted under rigidly controlled conditions of hospitalization and involved actual measurements – not estimations – of calorie intake and body weight.

But what about weight-loss studies involving people who are not incarcerated? Since the early 2000s, numerous clinical trials have shown low-carbohydrate diets to produce greater weight loss than low-fat diets. Some also have observed improvements in blood pressure, blood glucose levels and blood lipids.

But it is so inaccurate to estimate calorie intake in such studies that most didn’t bother to try. This means they can’t say whether the weight loss was due to composition of the diet or to calorie reduction.

It’s possible that low-carbohydrate, high-fat diets make people less hungry, but the evidence for this is mixed. Most studies of extreme diets of any type report high dropout rates or failure to stick to the diet for more than six months or so. And even though initial weight loss is rapid on low-carbohydrate diets because of water loss, these diets are low in fiber and some vitamins.

One problem with losing weight is that it takes fewer calories to maintain smaller bodies. Dieting also reduces energy expenditure.

One recent study of that problem involved taking detailed measurements for several years, and illustrates the difficulties of obtaining definitive answers to questions about diet composition and energy balance.

The researchers wanted to know whether diet composition affected energy expenditure in very obese people who had just dieted off up to 15 percent of their weight. They found that a low-carbohydrate diet did not slow down energy expenditure nearly as much as a low-fat diet, meaning that low-carbohydrate diets might make it easier for people to maintain weight loss.

On this basis, the investigators said, “The results of our study challenge the notion that a calorie is a calorie from a metabolic perspective.”

Perhaps, but study subjects were fed prepared calorie-controlled diets for only four weeks, and lost and maintained weight under highly controlled conditions. Does diet composition matter for weight maintenance in the real world? Longer-term studies by other investigators show that diet composition makes little difference in the ability to maintain weight loss.

Most reviews of the subject conclude that any diet will lead to weight loss if it cuts calories sufficiently.

Obviously, some diets are better for health than others.

Face it. The greatest challenge in dieting is to figure out how to eat less – and to eat healthfully on a regular basis – in the midst of today’s “eat more” food environment. And that’s a much more important research problem than whether low-carbohydrate or low-fat diets work better for weight loss.

Marion Nestle is an author and a professor in the nutrition, food studies and public health department at New York University. She blogs at E-mail:



  • Crider

    It’s the bulk, in my opinion. Both fat and carbs are quite concentrated sources of calories. I just went to one of those calorie-counter websites and entered some food items and found how many calories per 100 grams of that foodstuff:
    EV olive oil: 799 calories
    snickers bar: 475 calories
    white bread: 252 calories
    whole wheat bread: 228 calories
    sirloin steak, medium rare: 177 calories
    pinto beans, cooked: 145 calories
    granny smith apple, raw: 52 calories
    raw celery: 15.8 calories

    I have a neighbor that started out on the Atkins diet several years ago with all that meat and little carbs, and they did lose weight, but they also recently had to have a stint put into one of their heart arteries. They’ve moved on, and aren’t so dependent on all that meat. They eat lots of celery, but they dip it in ranch dressing (475 calories per 100 grams).

  • This is a timely post, because of a discussion we had around the table last night. Marion, you wrote that a LC diet is low in “some vitamins”.

    My husband has been reading sites that claim we can obtain every nutrient we need from meat. I am much more inclined to believe that a diet rich in fresh organic produce to complement high quality (preferably pastured) protein and fat sources makes more sense, if you were looking for an optimal diet.

    Could you please explain which vitamins are typically missing in a low carbohydrate diet?

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  • On a recent cruise, I ran one of my N=1 experiments. There were certain types of food I did not eat at all. But I managed to consume at least 3500 calories each day of a 7-day cruise. There were a couple of days I went north of 4500 calories. I gained about 3/4 of one pound that week, which is well within a typical daily fluctuation for me. I wrote up the protocol I followed on my blog.

    Let me hear you claim that cruise fare is actually “low-calorie food in disguise” or that I’m lying and I didn’t really eat all that much (I have witnesses).

    Calories-in-calories out? Oh, so I *must* have done a lot of exercise! Er, no. I did spend a lot of time soaking in hot tubs and laying in the sun, and one 15-minute session of weight training (which was interrupted by some “trainer” who has several years of study ahead of him before he is qualified to lecture me on diet or exercise). Oh, and I did take a leisurely stroll around a tourist trap with my wife on two different days.

    I know exactly what types of food I could have eaten in order to gain a pound per day on that cruise, because I’ve done exactly that on prior cruises. So I don’t do that any more.

    So far, I’ve lost over 120 lbs since 1999. Without “dieting,” restricting calories, strenuous exercise, prescription meds, or going hungry.

    And I know for a damned fact that calories don’t count, at least not in the way the mainstream diet industry insists. What counts is how you manage your hormones and what they in turn do with those calories.

  • Misdirections:

    Low Carb vs. Low Fat … One of the best quotes I’ve heard about LF vs LC is this:
    I always like to tell people: forget low-fat, low-carb, start thinking low-processed.

    Eat Less, Exercise More … One of the best quotes I’ve heard about EL, EM is this: If I’m hungry, I eat, and I don’t think twice about calories.

    If you’re consuming high nutrient and low density foods combined with the two nutrients that provide satiety, everything falls into place.

    Ken Leebow

  • brad

    @Howard: I think 7 days isn’t nearly long enough for these types of experiments. Try 700 days and come back to us with your results.

    I recently spent 2 weeks in Brittany eating enormous, long meals with family: lots of bread and jam at breakfast, three-hour lunches rich in carbs, four-hour suppers with multiple courses and different wines, sweet desserts, etc, a little meat but mostly seafood. I gained one pound.

    Two years ago I took a 10-day bicycle tour from Toronto to Montreal, about 700 kilometers. We burned hundreds more calories every day than we could consume. I weighed myself before and after the trip: I lost one pound.

    My point is that the body tends to deveop a set point for weight, and short-term perturbations in diet and exercise may not have much effect on your weight. In my N=1 experience, at least, it takes a longer, sustained change (i.e., months) to have any significant impact on my weight. I can lose weight more quickly by consuming fewer calories than I can by exercising more, but strangely enough if I consume more calories while not exercising any more than usual my weight doesn’t budge much for weeks, and then it starts rising gradually.

    I think there’s a time lag involved; I’m not sure what the mechanism is but may be related to the body’s general tendency toward homeostasis.

  • RB

    The problem I have when one talks about carbohydrates is that no one ever seems to distinguish between refined carbs found in soft drinks, bread, cookies, chips and deserts and complex carbs from nutrient rich food including vegetables, fruits, legumes, nuts and grains (real whole grains). I fine it hard to eat too much when eating from the latter form of carbs. Why does no one seem to distinguish between the two ways we get our carbs. I think it is a very important distinction.

  • The key question remains unquoted: The Daily PERSONAL Energy Expenditure (DTEE), which mainly depends from the Personal Basal Metabolic Rate (in part genetic driven) and Physical Activity (occupational, leisure, fitness and so on). Please read the related chapter in the book: Eating healthy and dying obese!

    Healthy greetings from Switzerland
    Leoluca Criscione,
    Former Cardiovascular and Obesity Researcher

  • @brad — Is 12 years long enough for you? I average about 2500 – 3000 cal/day, and have done so on a high-fat diet for that long. I initially lost 120 lbs (in about a year), gained back about 50, which I then lost again, and am now proceeding to lose more.

    Or, do I need to do it for 20 years? or 30? or 50? or what?

    BTW, in one 7-day N=1 experiment, I gained 10 lbs. That was a different cruise, and I added only one type of food I don’t normally eat. So 7 days is clearly long enough to establish some things.

    My N=1 experiments count, and they count for more than most of the crap that passes for “research” in the field of nutrition. That’s because my motivation is to find what works, and not to get more grant money from Monsanto, Pfizer, or Coca-Cola.

  • Anthro

    I follow Marion’s advice. And I read her books.

    I lost 45 lbs (I’m 5’ 2”) six years ago and have kept off 40 of it. I eat mostly healthy food from all food groups in SMALL amounts–the serving sizes that make you laugh or gasp when you actually pay attention to them. I count calories, but not slavishly. Lots of veggies, beans, and fruit, very little meat, and very little refined carbs. (Marion doesn’t say not to eat meat–I just hate factory farming and find that I can have more of other stuff if I don’t eat meat).

    I weigh myself every other day or so and adjust my intake accordingly. I am active (gardening, walking), but do not do any formal exercise although I lifted weights for years when I was younger and I think this has benefitted me in the long run.

    I drink only water, coffee (with half and half!), and the occasional beer or 5oz wine.

    People often ask how I did it. I always reply: “I ate less”. Most of all, I keep on eating less. Simple? Yes! Easy? Not always. You get used to it.

    I’m not perfect–I had a small bag of Cheetoes on my recent road trip! I nearly exploded from the salt.

  • Beenie

    Over the past 5 years, I’ve lost almost 60#. It’s been a nice, slow, steady loss, and it’s been relatively easy for me to maintain.

    How did I do it?

    1) I stopped eating junk. I no longer eat sweets, except for family celebrations (and I always go for the least amount of sugar possible). I aim to keep my added sugar intake as low as possible.

    2) Soda and other sweet beverages are forever banished from my house. I drink water, tea, herbal tisanes, and the occasional glass of organic milk.

    2) I prepare and eat most of my meals at home.

    3) I tripled my daily fruit and veggie intake to almost 10 servings a day.

    4) I don’t eat refined grains. Bread is no longer part of my daily diet (although, I still eat bread, but no longer everyday and only in small portions when I do have it).

    5) I increased my fish intake. I tend to prefer seafood over other meats. I’ve increased my protein intake to make my meals more satisfying.

    6) I don’t count calories. I don’t portion out my food. I don’t weigh myself (never have in fact. I don’t even own a scale for that matter). If I had to be a slave to scales, I’d probably shoot myself. I simply only eat when I’m hungry, and I don’t eat when I’m not. I eat slowly, with no distractions; I pay attention to my food; I enjoy it. I eat until I am comfortably full and satisfied, and then I stop eating.

    If a particular food doesn’t leave me energized and feeling well, I don’t eat it again. For that reason, I largely don’t eat bread products, pastas, or potatoes anymore.

    7) I walk 5 miles 4x a week, swim and do yoga the other three.

    And I’m not perfect either, I still have a serious dark chocolate habit. 🙂

  • brad

    @Howard: those are nice results, but 2,500-3,000 calories a day doesn’t tell us anything without knowing your height and weight. I can lose about a pound per week if I limit myself to a daily diet of 2,200 calories, because I’m 6’4″ and weigh about 180 pounds.

    As the other examples posted here show, eating less works, as does eating differently. Low carb diets work, but so do other diets. Everybody is different and every body is different: if you tend naturally toward insulin resistance you probably have better luck with a low-carb diet. But it’s pointless to universalize it and say “calories don’t count” or “eat less/move more is a failure,” because there are millions of people who can prove you wrong — just as there are millions of people who can demonstrate that low-carb is an effective way to lose weight.

  • Greg

    Dr Nestle, there is a serious mistake in this article. 27 pounds of fat * 3500 calories per pound = 94500 calories.

    70 days*800 calories = 56000 calories. It is not possible for out professor friend to loose that much weight, or at least fat, like that. I’m sure you agree it’s important not to create any more confusion regarding how hard or easy to loose weight it is.

    Or at least fat. If it was muscle making up the balance of this person’s weight loss that should be specified as it is an important fact.

  • To me it seems like calories matter most when it comes to weight loss, but that what you eat matters most when it comes to overall health. It just depends on what your goal is (but I’d hope for most people the goal is overall good health!)

  • Having just read Gary Taubes book “Why We Get Fat” I am wondering what you think of it? He seems fairly certain that the type of calories matter a great deal, and carbs are the worst for you. Thoughts?

  • Percy

    I just discovered today that a decent tool has been “improved” to indecency.

    For people who watch their carb intake but need a shelf-stable food product like cold cereal to eat at their office desks in the morning, Kellogg’s Special K Protein Plus was stand-out product in the cereal market place. While it did use some sucralose for an unnecessarily slightly sweetened taste (frankly, I would have been happy without that), each 3/4 serving was – as cold cereals go – pretty good for people eating a roughly isocaloric diet (that is, roughly balanced macronutrients of fat-protein-carb): 100 calories, 3g fat (on top of which would be fat from 1% milk), 14g carbs, 5g fiber, 2g sugar and 10g protein.

    Well, Kellogg’s this month has debuted a “new improved” formula worthy of New Coke. The New Protein Plus features these “improvements”: Caloric load went up 20% (to 120), sugar content when up 350%!! (from 2g to 7g), carb content went up 36% (from 14g to 19g), and fiber content decreased 40% (from 5g to 3g). Fat content decreased, but it’s actually better to have some fat with those carbs, to slow down their digestion a bit. The audience for this niche cereal is rebelling on social media.

    Marion, might you cover this “improvement”?

  • brad

    @Percy: Kellogg’s has done this before, with Nutri-Grain. Back in the 1980s that was the only cold cereal I ate because it was very low in sugar. At some point, maybe in the 1990s, they changed the formula and made it sickly sweet. It was the first time I felt motivated to write to a manufacturer to complain, and I did — as did about 20,000 other people. Kellogg’s was surprised at the feedback and they did the right thing: they reverted to the old formula. I got a letter from them along with coupons for two free boxes.

    You could try the same thing. If enough people complain, they’ll listen.

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  • Margeretrc

    Sure, someone who is not insulin resistant can lose weight simply by reducing calories (some–too much and metabolism slows) and moving more. No argument. My daughter did that recently. But she has to keep careful count of everything she eats and get up at the crack of dawn to run. Perhaps, as Anthro has, you can even keep it off by being a slave to portion control, exercise, and watching calories. That’s what my daughter is doing and yes, she’s keeping it off, too. But as far as I’m concerned, that’s no way to live–really live–the rest of one’s life. At least, not for me. I made up my mind 7 years ago that the only “diet” I would go on was one I could do for the rest of my life without hardship. So I ditched the fear of fat, switched to real food, and began eating a little of everything–as long as it was real food, watching portion control but not calories. I savored my food and learned to know when I was full. I did that for 6 years and didn’t lose a pound. In fact, I gained some weight, though not much in the way of inches–I didn’t grow out of my clothes, even if I wasn’t shrinking out of them either. I was exercising, often a lot. I probably would have been reasonably content doing that for the rest of my life. Then I got reacquainted with Gary Taubes’ work and I decided to try low carb, high fat. That was a year and a half ago. I pretty much ditched bread, pasta and such (I still eat carbs, just not grains, sugar or starchy vegetables. The carbs I do eat are nutrient dense, but not carb dense. ) Not only did I lose weight, but more importantly, I went down two sizes and streamlined by body quite a bit. And I did this without any hunger or discomfort, calorie counting or portion control, or increasing how much I exercise. However, my energy and endurance sky rocketed so that it was much easier to maintain the exercise regimen I had gotten used to. I eat as much as I want to when I want to–of really good stuff like bacon, eggs, and fatty meats, cream, cheese, non starchy vegetables and low sugar fruits–and the weight stays off. In fact, I continue to lean down slowly but surely. This I can do for the rest of my life, no problem, and I intend to. To each his own, but if you want a painless, relatively easy way to lose weight and keep it off, low carb wins hands down–without sacrificing health, perhaps even improving it. Yes, calories matter, but that doesn’t mean we have to count them. I don’t. And I don’t intend to ever again.

  • I believe there is not much in dieting one should eat and try to stay busy as long as you are doing some work your calories will burn out themselves there will be no need for dieting.

  • Jen

    A calorie is not a calorie – In fact calories don’t actually exist they are a unit of measure that describes the amount of energy created when burning food in a metal oven… humans do not have cast iron stomachs. The middlesex study that took place in 1950 clearly showed the difference. Check out this blog:’s-not-about-calories-part-1/

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  • Great article, I would like to study my favorite.I Like..Here..5 Steps To Looking 10 Years Younger.even if your calories stay the same.Younger school body!I know you do

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  • “Low-carbohydrate diets are necessarily high in fat, and somewhat higher in protein. Do people lose weight on them because of the effects of carbohydrates on insulin levels or because low-carbohydrate diets help reduce calories?”

    the former for some, the latter for some, both for some, and neither for others.

    If you are getting nourished by your diet, things are going to go better.
    Eggs and liver are fairly calorie dense, but their nutritional value relative to their calorie value is high.

  • Lidia Hankins

    I was overweight and tried so many things. Different things work for different people and I was lucky enough to find one that worked for me. I lost 19 pounds in one month without much exercise and it has been a life changer. I’m a little embarrased to post my before and after photos here but if anyone actually cares to hear what I’ve been doing then I’d be happy to help in any way. Just shoot me an email at and I’ll show you my before and after photos, and tell you about how things are going for me with the stuff I’ve tried. I wish someone would have helped me out when I was struggling to find a solution so if I can help you then it would make my day

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  • carletouk

    I’ve done calorie counting low carb and calorie counting balanced diet . And long term the results are the same . The only difference is I feel better on the balanced diet . So I stick to that .