For many decades I thought "a calorie is a calorie," meaning that I expected to lose equally well on all diets, so long as the calorie intake was the same (so I would theoretically lose as much weight on 1500 calories of candy as on 1500 calories of beef as on 1500 calories of brussels sprouts).

Since this sage piece of wisdom first came to me from my pediatritian when I was 12, I didn't question it for many years.

Only now there's more and more research that is finding that all calories do not burn equally (and some don't burn at all) in the human body.

There are at least 3 types of calories that don't "count" the same as others (and a couple more possible maybe ways).




1. Fiber (cellulose)

The first "non-caloric calorie" I learned about was fiber. A carbohydrate than humans cannot digest at all. The calories in cellulose, pass out of our body without being digested (so they don't count). And yet most calorie-counting resources still include fiber calories in the total (making vegetables and fruits seem higher in calorie than they really are).

Flax seeds for example, have zero useable calories unless the seed coating is broken. And more calories will be accessed if the flax seeds are ground rather than simply just broken.



2. Sugar alcohols

Sugar alcohols are trickier. How many digestible calories do they contain? Some research suggests that different people have differing abilities to digest sugar alcohols. Some sugar alcohols tend to be more easily digested than others and some people seem to be better able to digest them than others (meaning for example that xylitol may contain fewer useable calories for me than for you, or vice versa).

Sugar alcohols are a bit of a double edged sword, because if you're sensitive to them (can't digest them well) you get diarrhea, and if you don't get diarrhea that could be an indication that you are digesting them just fine (and therefore absorbing more of the full 4 calories per gram).


3. Resistant starch

These un-calories (unburnable calories) are found in whole grains, legumes, underripe bananas, and in some cooled starches (and if you reheat these foods, the resistant starches are broken back down into digestible starches).

These starches are also undigestible - or less digestible than other starches, and act more like fiber (which many of the diet experts consider them).

This means that an ice-cold potato has fewer digestible calories than a hot one, but how many fewer? How do you know how much of the starches have been converted to resistant starch?


And for the maybes:


4. Low-carb eating (at least for some people)

While it's been argued by low-carb advocates for decades, research has finally confirmed that people really do burn more calories on low-carb eating. Recent research found a caloric advantage averaging about 300 calories for a low-carb diet like Atkins (an a caloric advantage averaging about 150 calories for a moderate-carb diet such as the Mediteranean diet).

So carb-restriction apparently can increase the rate at which your body burns calories (for some folks).


5. (maybe) Medium chain fatty acids (found in dairy and coconut oil)

The research here is still too new and sketchy for me to be convinced, but the theory goes that these fats boost metabolism, reduce and postpone hunger, banish fatigue and boost energy levels making exercise easier and more intuitive (you'll supposedly just naturally want to move more).



Resistant starches are the most intriguing to me. I'd love to be able to add (some) carbs back into my diet (even if I had to eat them cold to do it), but of course the biggest problem to me is knowing how much of those carb calories will my body digest. Half? 90%?


Of course I can always experiment (doesn't it always boil down to that anyway?)

I find all this fascinating, and frustrating (because I want to KNOW that I'm eating the best diet for my body and for my weight loss, and I can't ever know with absolute certainty, because there's too much we just don't know - even the "experts" who've made it their lives' work to know everything that can be known about the subject).

Fascinating post. I always thought a calorie was a calorie too. I remember reading the book "Stop the Insanity" by Susan Powter and that challenged my thinking. If I remember correctly for her it was fats that were considered more then the amount of their calories.
I find I do better on a lower carb diet for sure. And I am simply more full having more protein with fewer carbs. But I do not ban carbs I eat less of them then of other foods. However I do eat plenty of veg and fruit.
Well if you experiment with the cold potatos I hope you post your findings.

It amazes me just how much diet advice is just totally wrong and unhelpful. Protein takes more energy to burn so it has been said that it burns 4 calories per gram just to digest and you get about 6 calories per gram. So say you eat 100gs of protein in a day you burn off 400 calories just digesting it. But you eat mostly carbs and you get 400 more calories.

So net calories from protein gram is 2 calories. But on any nutrition facts it wouldn't be reported that way.

Here is a question though... why can't we do some experiments on the net. I mean get a message board and get people to do controlled experiments and report results. Even if it wasn't "scientific" wouldn't it at least give us more information than we have now... with conflicting studies. I don't know.. I don't see why dieters don't try to get results on their own.

A calorie has never just been a calorie for me, either. Not for someone contending with a genetic predisposition to metabolic syndrome, with the trigger pulled by years of not knowing how to eat without aggravating it. No. High fat, moderate protein, low carb goes well for me, and calories from fat and animal proteins metabolize much better with my body than calories from starchy produce, grains, beans, or ANYTHING refined to more sugary proportion. Such is life, and every body is different!

Wow. This explains a lot. I too always assumed that a calorie was a calorie. I've got to be more careful about sticking to my target F/P/C %s. Thanks for the clarification.

I will, but I can't imagine experiencing results dramtic enough to provide significant information.

I also feel best and lose best on a fairly carb-restricted diet, and carbs tend to fuel my hunger, so I can't imagine tempting fate by eating more than an occasional serving of cold beans or potatoes. Even if I experience no ill effects, I can't imagine eating more than one serving per day, and at only about 80 calories, per - I'm not sure I will notice any measureable effects at all (after all, that would amount to about 1/6 of a lb in differential weight loss).

Even if the calorie math is off, the laws of thermodynamics still apply, so every calorie in a food at least has the potential to be burned in the human body. Even if some of those calories aren't burnable, I'm not sure the difference is ever enough for a single person to be able to detect the degree to which a food burns (unless you're ONLY eating that food and then compare your loss - after several weeks - to several weeks on ONLY another food).

I'm not dedicated enough to science to perform those kinds of experiments on myself, so at best I'll be able to tell you whether or not I've been able to add in an occasional serving of cold beans or potatoes into my diet without apparent detriment to my weight loss or will power.

Waxy potatoes (like yukon gold, baby red, and other smooth skinned potatoes) have fewer calories than starchy (rough skinned) potatoes (like russet), and the skin is mostly fiber, so I do try to choose the tiniest waxy potatoes I can find (so there's a higher skin to flesh ratio).

In our farmers market, we have vendors who sell pea and grape sized potatoes (hubby and I both love these). I usually have eaten them hot, but recently when I was craving potato salad, I made a potato salad with 3/4 diced, steamed cauliflower and 1/4 pea/grape sized potatoes. I also used a mixture of light sour cream, full fat mayo and Hellman's olive oil mayo for the dressing (Hellman's canola mayo and olive oil may both have about half the calories of regular mayo).

I also added about twice the celery, onion, and bell pepper I usually use (all strategies to increase the volume and decrease the calories per ounce).

I did have a somewhat "addictive" response to it. I ate more servings than I intended to, but I did stay in my calorie/exchange limits for the day, and I didn't see any measurable help or hinderance ot weight loss.

I think I'd have to eat more than I'd want to, to draw any useful conclusions.

I've surprised to see you post this. While I am a proponent of low carb dieting for most people who want to lose fat this study while interesting doesn't prove low carb dieting is creating a metabolic advantage in my opinion.

I admit I haven't read the full study but from reading the abstract and some write ups about the study it was well designed but did have some limitations.

First of all it was only 21 participants, second they were formerly obese, third they were not measured well enough to establish a baseline, protein was not matched across all diets, and finally it was only four weeks. (If I'm wrong about any of these limitations please let me know)

As you're probably aware there are other studies done on young not obese participants that shows the exact opposite.

There was a lot of variability between participants as well - which shows one thing is for certain - we're all a little different in how we process carbs.

Bottom line is that we learned some interesting things if you test a bunch of insulin sensative young people you would have had quite a different result.

Still though - as I said - I always suggest lowering carbs. If nothing else low carb seems easier for most people to stick to for a number of reasons.

I have always completely disagreed with the idea that "a calorie is a calorie." Our bodies are designed to process natural foods such as fruits and veggies... not a bunch of artificial stuff that is in most processed foods today.

Ooh, very good catch John. You raise a point that I actually meant to address.

When I said there were at least three ways in which calorie content didn't necessarily translate directktly into calorie impact, I neglected to mention that #4 and #5 were "gray area" points - although #3 is a bit gray itself, so I should have been much more clear about which were gray area points.

I agree that the study is limited and there needs to be a LOT more research and longer term research into who experiences the low-carb differential and who does not (and what variables affect or determine who does and does not).

Unfortunately, many of these studies use a type of statistical analysis that doesn't identify individual differences, and when you don't look for individual differences, you don't find them, you only find the trend. Thus (to grossly oversimplify) if half the participants experienced an advantage to low-carb, and half experienced a similar disadvantage, the study would falsely conclude that low-carb had no effect at all. Now, if that were dramatically the case, the researchers would have noticed in compiling the data, and would have chosen a different type of statistical analysis to catch and measure that effect - but if the results were subtle, they might not. Or if it occured in only a small percentage of participants, the researchers might not notice, or might conclude that the "exceptions" were statistically insignificant.

Far more research has to be done to determine whether low-carb has an advantage (or can have an advantage) and for whom - because I believe that you're very correct on this point - that the amount of differential (and even if there is one) may very well depend on a host of variables.

I sometimes forget (or forget to stress) that some of my conclusions are based on my own very unscientific experiments, so when I see research that reflects my experience, I can get overexcited about it, and forget to point out (and sometimes don't even see all of) the weaknesses of the research.

I suspect that age and insulin resistance are two of the most salient variables when it comes to experiencing a high-protein, low-carb advantage (and I'm not sure whether it's the low-carb or the high-protein that accounts for the advantage when it DOES appear to occur).

However, my suspicions and personal experience aren't enough to conclude much of anything (and why I didn't mean to implicitly conclude that low-carb/high-protein were definite sources of calorie differential).

I know for myself, I experienced much less differential when I was much younger. I seemed to lose about the same on low-carb as on high-carb (though I also admit I didn't try low-carb long enough to draw any firm conclusions - except that very low-carb made me very ill, probably because I had blood sugar issues even then).

Now the difference is so dramatic (about the 300 calories the study found) that I was hesitant to even mention it here for more than two years after discovering it, because I wasn't confident that I was seeing what I thought I was seeing (initially), and even when I became confident in my experience I was still hesitant to share it, because of how it would sound - how ludicrous it seemed. I wouldn't have been much more reluctant to report an alien abduction (which by the way I HAVE NOT experienced, just to be clear).

Weight loss research is still in its infancy, and the kind of closed-system research that would be the most informative, is also the most expensive, and the least likely to be conducted.

As the character Dr. House often says in the medical drama, House often says, "people lie," and so weight loss research shouldn't have to rely on unobserved behavior (and yet it does).

Closed-system research in which participants live in a closed environment, in which food intake and other variables such as exercise can be closely observed (and participants cannot smuggle in food or otherwise eat off-plan) is extremely expensive, and not very attractive to either researcher or research participant. In most cases, research participants want to be able to lead a reasonably normal life during the course of the study, and most researchers don't have the funding to provide room and board for study participants and for staff to monitor participants 24/7.

Also, because of my own experience with my youthful metabolism being so very different than my current aging, disabled one, I suspect that the research has to be conducted with the assumption that there will be huge individual differences, contingent upon countless variables - and unfortunately MOST of the weight loss research doesn't go in with this assumption (or when it does, the researchers often fail to address the issue or at least the mentioning of it - rather they gather as homogenous a group as possible to avoid dealing with the individual differences and treat the study results as if it somehow reflected the entire population).

There's a LONG way to go, before weight loss variables are entirely understood, even the single variable of calories in/calories out.




I also don't mean to imply that "calories do not count or matter" or that calorie counting isn't a useful tool. Ultimately the laws of thermodynamics and conservation of matter apply. It's just important to realize that the human body is not a furnace, and it doesn't utilize every calorie that comes in (affecting the calorie "in" part of the eqation) - and that the calories that come in and are used can affect the "calories out" part of the equation.

I'm not ready to toss the baby out with the bathwater. Calories matter and they definitely count, there are just many variables that affect how much they count for.

It's been common practice to treat 100 calories of oreo cookies (2 cookies) as being fundamentally equivalent to 100 calories of lean protein or 100 calories of apple, which doesn't seem to be the case (at least not 100% of the time for 100% of individuals).

I believe the research is just starting to address the more complex variables of calorie intake and weight loss.

I completely agree with this. I've heard "It's just calories in vs. calories out" for so long. And for some, it's just that basic. But if I have a bowl of oatmeal with fruit and nuts in the morning I will gnaw my arm off by 10 am. Ooooor.... I can have an egg white scramble with some turkey bacon/sausage or ham, toss in some veggies covered with salsa and I could be good 'til 1 or 2pm if necessary.

I don't know the science of it all but I know for me I am much more satisfied with a higher protein diet than one high or moderate in carbs. Sometimes I forget this (ahem, this summer ) but I try to stay on track because I feel better when limiting carbs, even the complex, unrefined variety. I actually have found the more carbs I have, the more I over eat, I over eat carbs which leads to more over eating. It's an endless cycling until I just cut back on them altogether.

And sugar alcohols? Regardless of how they count calorie-wise, they're a no-no in my house. They do wicked things to just about everyone in my family. It does NOT make for a pleasant day!

Thank god. I think the reality is that food is extremely complex... not just for dieting but for health in general. You just can't eat anything and expect the same result in every human being. I think studies are essentially verging on the edge of useless because so many have been done that claim to have a result but upon further review you find out they are missing some crucial variable.

Also, studies imho are being done 99% for commercial food interests. So for example... a study comes out that says milk is crucial for weight loss only the study turns out to be sponsored by some dairy industry. A lot of times I will see a study that says something like "Vitamin D" has no effect on weight - but if you look at the study you may find out that the amount of vitamin d given was low and it was a kind that was not easily absorbed. Vitamin D2. So it seems like a lot of studies are just kind of proving what they wanted to.

A few things I have seen recently suggest that carbs now may not exactly be the same as 30 years ago. That they may be genetically altered and have 100 times more effect on your blood sugar. I have no evidence other than circumstantial. Diabetes is an epidemic but could human beings basic behaviors be *that* much different now than 30 years ago? I doubt it seriously. Not to mention that I see as much fat in highly disciplined very successful people as not.

Actually, the answer is very much yes. The "trend" towards diabetes and obesity has been beginning since the dawn of agriculture. The paleo diet gurus argue that diabetes is virtually unknown in non-agricultural societies (not just in "cavemen" but in modern hunting/gathering societies - though it's getting harder and harder to find the hunter-gatherer following their traditional lifestyle - such as some indiginous peoples in the arctic (inuit), some aborigial peoples in Australia and New Zealand, and some amazon tribes in the deep jungle...

You start to see diabetes in agricultural societies (the prevailing argument amongst the paleo proponents is that the grains are to blame), and it only reaches modern proportions with a modern diet.

The modern diet is much higher in refined and processed carbohydrates than it was only ten years ago, whch was much higher than twenty years ago, which was much higher than 30 years ago...

For the past 60 years, our carbohydrate intake (especially refined carbs paired with fat) has risen exponentially - with more change occuring in the past century than in all of the previous 15,000 years combined.

And our activity level has plummeted. We don't walk, stand, or even wait in line standing as we once had to. Even manual laborors burn fewer calories than their predecessors of only a few years. Every year the tools we use, allow us to burn fewer and fewer calories, and yet we're concentrating our food sources so they contain more and more calories, but less and less nutrition. Even our healthy food is less healthy, because of our farming practices (which deplete the soil of nutrients).

Our hobbies are less active as well, so people of every income bracket move less than their ancestors - and if we're not on the tail end of the trend (and it doesn't appear that we are) then our children will be doing less and eating less well than we are, and their children will be doing even less and eating even more poorly.

In the 1980's most families (if I'm remembering the research timeline correctly) ate out roughly once a month (which was dramatically more than in the 1960's) and now the average is something like several times a week (and that's not even taking into account the processed ready-to-eat foods picked up at the grocery store).

Even in my own lifetime, and my own family, the changes have been dramatic. I just spent two and a half weeks with my family in Illinois, and their lifestyle is almost unrecognizeable (from what it was only a few years ago).

When I was growing up, we went out to eat only on very special occasions and fast food was pretty much something we ate only on vacations (when we had to eat in the car). My mother and grandmother cooked, and mostly from scratch (potatoes and carrots had to be peeled, salads didn't come in a bag).

When I was a teen, we started eating fast food more often as our lives became busier.

And when I went to visit my family, I found that my family (my mother, father, sister, nephews, and brother-in-law) eat out several times a week, and my mother now cooks only on special occasions. The meals they now prepare almost always contain convenience foods, and frozen dinners aren't at all unusual.

When I was growing up, we had a bag or two of chips in the house and we were supposed to only eat them with lunch or an occasional treat. Now my mom has a "snack bucket" in the house from which the kids and adults eat whenever they wish (which turns out to be several times per day). Most of the snacks are those that are marketed to seem healthy, such as fruit snacks (which are really just fruit-flavored gumdrops) and whole-grain baked chips (which are almost as high in fat as regular fried chips), and bags of dried fruits (which have some vitamins and fiber, but are so high in sugars they really should be considered candy with some vitamins and fiber).

They eat oatmeal for breakfast, but it's sweetened, flavored instant oatmeal (which often has as much sugar as a piece of cake)



Cooking from scratch is becoming a lost art. You can't even FIND many traditional foods in a supermarket unless there's a large ethnic population that's still using them - and then they're expensive because they're considered specialty items.

Hardly anyone eats organ meats any more, and other traditional foods are also becoming "lost" because they're either difficult or time-consuming to prepare.

Animals get sick if they only are eating muscle meat - and no wild animal can afford to be so picky as to only eat the muscle. They also eat the skin, and the internal organs to get a balanced diet.

We're not carnivores of course, but we are ironically eating a less balanced diet now than in previous generations - a much less balanced diet, when we can least afford it (when we're so sedentary).

In previous generations, even the poor (especially the poor) ate a wide range of fruits and vegetables cultivated in gardens and and scavenged from the wild. Ten to 15 servings wasn't unusual, and now many people eat no vegetables whatsoever (unless you count potato and corn which more rightfully should be considered starches).

And we're breeding the fiber out of food, and more and more sugar into foods (and not just the ones we're going to turn into processed junk food). Today's sweet corn, potatoes, beets, apples, and just about all fruits and vegetables are bred to contain less fiber and more sugar than their heirloom counterparts. We also selectively breed our produce to look nice longer, rather than for heathfulness. We want our produce to look good and taste good, and really don't care if that means breeding less healthful food.

Even those of us who've experienced the drastic changeing of lifestyles don't realize how much things have changed, because the change has been gradual enough that it just seems like we're doing what we've always done, but it's just not true. We're eating far fewer fruits and veggies, more starch and sugar, relying on more and more processed foods and we're moving much less.

The food we're eating today barely resembles food of 30 years ago, let alone 100 years ago.

I don't know... seriously. We do have gyms now and there isn't anyone I know that doesn't go. When I think about my mom she never used to do any exercise at all and she still wasn't that fat. Same with my dad and he had a desk job. I just don't know.. I mean a small contributor... maybe but there has to me something in the food that is tipping it severely over. I still see fat construction workers manually laboring all day long outside my work window.

I am sure it has *some* effect but I can't believe it has that much. I just can't. For example say the average American has 50 extra lbs. I can say that 25 might be caused by the factors you mentioned but I feel 50 is a sign something else is up. Just my gut here.

I think everyone is a bit different in regard to carbs, sugar, etc. Two years ago i was in a shelter (long depressing story). It was summertime, and we had to be out of the shelter from 8am till 4pm. I had nothing to do but walk.. i would walk to the library, parks, etc.. during that time i was depressed and not thinking about what i ingested at all. for breakfast i would have a couple donuts. then about 10am i would buy a 99 cent bag of chips and a full sugar soda. lunch would be a sandwich on white bread( we packed our lunches at the shelter and that's all they had), cookies (3-4), and another soda. then in mid afternoon, i would have more chips, and usually some peanut butter pretzels as well, and another soda. then eat dinner at the shelter which was usually very carbi. I lost 32 lbs in about a month and a half eating this way. Now granted, i was walking quite a bit. about 3-5 miles per day.
I have a friend that is on a low carb diet cause if she has many carbs, it stalls her weight loss or she gains, even tho she stays at her calorie limit. i think everyone just has to try different things and find what works for them.
this time, im not in a shelter, not depressed, and not eating the way i was back then.. for two reasons. 1. it wasnt healthy.. 2. i dont walk as much.. i am calorie counting now (1600 per day) eat what i want as long as its in my cal range. i do include one can of mountain dew per day as ive been weaning off of it(used to be 4 liters per day or more), and i have lost 9 lbs since the third of this month. so that works for me.. but i understand it doesnt work for everyone. it would be so much easier if we were all the same that way, and could just buy an instruction booklet on losing weight lol

edit here: when i said i eat what i want now i mean things like wheat bread, brown rice, .. not junk food lol

Simply speaking, relative to our incomes, food in America is cheaper and more plentiful than ever before, and junk food / fast food is generally cheaper than a Paleo-type diet. We eat a lot more than we used to.

You might find this interesting:
http://thesocietypages.org/graphicso...ition-circles/
The upshot is that according to the USDA, Americans on average eat over 500 calories more per day now than they did in 1970.