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Not All Calories are Equal. Indeed?

October 20th, 2010 Leave a comment Go to comments
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In mathematics, there are certain axioms, universally accepted truths. For example the shortest distance between 2 points is a straight line. 2 +2 =4. These axioms serve as the foundation for science and engineering progress.

In nutrition, the “calorie axiom” states that a calorie is a calorie no matter where it comes from – fat, protein, or carb.

But some scientists are now claiming that isn’t so. It’s not just the calorie, it’s also it’s source of the calorie. Here’s more from ABC News:

Jonny Bowden, a certified nutritionist and author of Living Low Carb, (Sterling, 2010) insist that all calories are most certainly not created equal. As proof, he points … Swedish investigation where volunteers snacked on candy or peanuts to the tune of about 20 extra calories per each half pound of body weight. For example, someone weighing 150 pounds would overindulge by eating a gut busting 1,300 calories a day.

After two weeks … the peanut snackers did gain a small amount of weight but only about a third of what the candy eaters gained and only the candy group showed an increase in waist circumference, cholesterol and overall blood fats.

“The reason for this is that the simple carbohydrate calories found in candy kept goosing the levels of the hormone insulin,” Bowden explains. “Insulin signals sharp increases in blood sugar and enhances the storage of body fat, so when it’s constantly elevated you’re primed for weight gain.”

Bowden says that, because peanuts contain virtually no carbohydrates, they don’t trigger the same effect on insulin and the body doesn’t rush to pack on the pounds. Even more interesting is that peanut eating group alone experienced a significant rise in their resting metabolism. This could indicate that the fats and proteins from the nuts rev up the body’s ability to burn calories which might also help suppress weight gain.

Researcher Richard Feinman, a professor of biochemistry at the SUNY Downstate Medical Center in Brooklyn, notes that insulin sensitivity impacts how you experience hunger as well. “It’s a well established fact that eating protein increases satiety and if you feel fuller on fewer calories then you are going to eat less,” he points out. read more…

What you need to know:

This one has got us scratching our head. A calorie, after all is just a measure of energy. The first law of thermodynamics says that energy can be transformed (changed from one form to another), but it cannot be created or destroyed.

Each bite we eat contains a certain amount of energy, regardless of it’s source. 100 calories from fat or 100 calories of carbs is still 100 calories. Once those 100 calories slide down into our stomach, they can be converted to immediately usable energy OR stored energy (fat). Do certain food types promote one over the other in a substantial manner? That’s probably the main point of disagreement in the scientific community.

Some scientists are also exploring genetic factors that cause different people’s metabolisms to react differently to different nutrient types. But there’s a long way to go before studies mature into individualized meal plans.

One thing’s for sure – on average we are consuming way too many calories, no matter the source. Even if you eat just unprocessed, whole foods, but rake in much more calories than you spend, you’ll be gaining weight. The optimization of 100 calories more  of protein vs. carb vs. fat is second order of magnitude when compared to the need to reduce total calorie intake by 500.

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  • Bill

    I agree with your conclusion that most eat way too much, but there are a number of issues with the article. First off, the shortest distance between two point is a straight line is only true in Euclidean geometry, it’s not a universal truth.

    Ignoring the geometry, I believe the problem with calorie in is that they don’t measure the amount of calories you get from food based on how we get them. Burning food in a laboratory container to see how much potential energy is contained is a lot different than eating, digesting, and eliminating unused food. Simple carbs are easily digested and stored. Higher fat / protein foods, esp. with fiber are not. It’s not that the science is bad, it’s just greatly simplified and needs more study.

  • http://www.theslowcook.com Ed Bruske

    Yes, it’s true. The law of thermodynamics is trumped by insulin as the body’s mechanism for storing fat. For a complete understanding, try reading Gary Taube’s “Good Calories, Bad Calories.” It’s by far the best objective review of obesity science.

  • http://www.foodierelations.com Jeremy

    You touched on a critical point – the calories can either be converted into immediately usable energy, or stored as fat – but this point is bigger than it seems. The human body is a complex system that “decides” what to do with incoming calories. What if eating certain kinds of foods signaled it to “change its mind” on strategy, from storing them to burning them, or even to burning existing stores? If that were the case, then what you eat now can have an impact on how the body processes more than just that food, but also food that you’ve eaten in the past or will eat in the future! Incoming food could be a signal that gets amplified, like a slight push on the gas pedal controlling a powerful engine.

    We already know this is the case in certain situations. For instance, if you go on a starvation diet, the body will actually break down the proteins in muscle for energy, even if fat is available! Why? Probably because evolution “trained” our bodies to respond to lean times by cutting down on expensive-to-maintain muscle – just like a struggling company lays off workers (muscle) rather than spending cash reserves (fat). To be most successful in a host of changing circumstances, evolution should have equipped us with a variety of “body strategies” for dealing with different situations, and to respond to environmental factors like the kind and amount of food being eaten to switch among them. We would also expect the body to respond to signals like physical activity to determine whether to store or burn fuel. So exercise should play a bigger role than just the calories it requires at that moment – it should signal the body to adjust strategies as well.

    We certainly don’t have all of this unraveled yet, but some simple thinking about complex systems and evolution gives us a framework for understanding some of the things we see and predicting some things we don’t yet know for sure when it comes to the relationship between diet, exercise, and physiology. It is certainly a gross simplification to think in terms of simple calories-in, calories-out dynamics.

  • Lea G

    A calorie may be a calorie but calories are not all food is made of and not the only thing affecting our bodies when we eat. Therefore certain foods, like candy, make it more likely that weight gain will increase faster than a high protein food like peanuts. This makes perfect sense to me. And I don’t think there are many absolute laws in science since it is based on nature and nature seems to grow and change and we just don’t quite get it yet. Certainly I would think two people eating the same number of calories, but one coming completely from high sugar high carb foods while the other coming from high protein high fiber foods will show two completely different bodily reactions to the foods. The calorie content aside. The problem is how our body chemistry reacts to sugar. I’m no scientist but this is what makes sense to me from the various things I’ve read and seen. :)

  • Mari

    If you eat or drink something sweet (or of high glycemic rating), you will be eating something ELSE sooner than if you are eating more nutrient dense, lower glycemic items to offset the insulin response.

    So while that 600 calorie cookie might not make you fat on its own, you’ll sure be eating something else a lot sooner than you would be if you had 600 calories of salmon and kale. If *only* because a cookie isn’t (“filling”, “a meal”, “very substantial”).

    I’m a fan of saying…”it wasn’t the [cookie], it was what i ate because of the [cookie]…”

  • http://www.chefmike.ca mike benninger

    Thank you Lea for stating that “…I would think two people eating the same number of calories, but one coming completely from high sugar high carb foods while the other coming from high protein high fiber foods will show two completely different bodily reactions to the foods…” in a far more clear way than I could.

    I would find it astonishing that a body would treat 400 calories from a Coke and bag of Doritos the same way it does from a glass of 2% milk and roast beef on whole wheat. YES, the calorie number is 400, but from 2 totally opposite sources, and i cannot imagine the body reacting the same, regardless of what science says.

  • Kimberly

    I second the recommendation for ‘Good Calories Bad Calories’ by Gary Taubes. It’s an in-depth review of nutrition science (over 60 pages of bibliography, and many, many more pages of notes). If you are interested in nutrition (and, obviously, you are) it’s a must-read.

    The problem with looking at calories in = calories out is it ignores the biochemical processes that are involved in the body–insulin, hunger regulation, increases or decreases in metabolism.

  • http://foodtrainers.blogspot.com Lauren Slayton

    When I talk to clients about this I also talk about satiety. I think Kimberly was touching on this. If I eat 100 calories of protein/fiber I am also subsequently going to eat fewer calories (if I listen to my body) than if I eat 100 calories from toast or sugar. To me this is one of the great shortcomings of weight watchers in that clients say “on weight watchers I could eat a piece of pizza with my points if I wanted to.” To me, points and calories are not created equal. I like your conclusions that the bottom line is that most of us could eat fewer calories for starters but I would flip that and say most of us can eat better foods too, even if portions or calories don’t decrease as a first step.

  • http://www.awakenedwellness.com Rachel Assuncao

    Of course the calories from two different foods are not created equal and are not treated the same by the body. If I ate 1600 calories from McDonald’s every day, I’d end up not only fat, but probably really ill. If I ate 1600 calories of beautiful, fresh, organic vegetables, whole grains, and maybe some nuts and seeds, I’d be energized, vibrant, and probably down a few pounds too.

    I think you have to take it a step further from this obvious comparison though. When I work with clients, some people experience the most health benefits with diets that contain meat, while others benefit from a more vegetarian approach. Some benefit from having dairy, while others do not. Some benefit from plenty of whole grains, others need only a little.

    I believe that once you have sorted out what (whole) foods are best for your body, it becomes nearly impossible to over eat. You are satiated on the mental/emotional level by great tasting food and your body feels full and satisfied because it’s getting the right nutrition for you.

  • http://www.afoodiestaysfit.com Teri [a foodie stays fit]

    Wow, that’s a pretty fascinating study. I’ve never really thought calories were equal because just intuitively it doesn’t make sense to me that someone can eat 2000 calories of junk and I could eat 2000 calories of real food and have us maintain the same weight ratios. But regardless of the ultimate answer, I know that I simply feel better when I eat calories from healthy sources!

  • Mari

    I guess, in a DAY if I ate the same number of calories, McD’s to Farmer’s Market, obviously there’s the nutrition issue. But I think the problem here, that we’re all saying is that meal to meal, is where the problem is. Like Mike is saying. It’s hard to compare a full day, since this is all reactive to what was ingested in the last sitting.

    So evaluating it by the day or [2000] calories shouldn’t be the focus.

    You guys have me wanting to read this book now.

  • MrEvil

    It’s got nothing to do with thermodynamics, it’s got everything with the body’s ability to extract energy from a given foodstuff. Take for instance an orange vs juice made from that same orange. Both have the same number of calories, fiber, nutrients etc… but in one form those calories are rendered more accessible due to the processing of that food and would be more readily absorbed by your body. The orange in it’s natural form has all of it’s sugars bound up in fiber making it more difficult for your body to process, thus limiting and delaying the intake of those sugars.

    Another example might be corn or peanuts. In it’s raw form it may have the same number of calories as the creamed/pureed form but it’s obvious that not all of it is processes by my body rendering those calories inaccessible.

  • http://www.rochesternutrition.com Carol Plotkin

    We can argue the nuances of metabolism and all end up in different places. 1. The body is not mathematical 2. Protein containing foods require more energy to digest, absorb and process than carbohydrates 3. Yes, there is that insulin thing, but it’s not all about insulin. and 4. Fooducates final statement is the take home message, people eat too many calories of all types, I know I can. Instead of blaming it on being perimenopausal and making excuses, I’m actively trying to eat less. Everyone should!

  • http://msxj.wordpress.com/ xj

    Very interesting post! I used to think calories are calories regardless of the source. But I’ve recently changed my eating and now I am not so sure! I’m betting on the side that says the source does matter! And I’m hoping there’s more information about it soon.

  • Bill McNye

    An engineering profesor of mine use to say “in equals out… unless it doesn’t.”

  • http://www.feedyourheaddiet.com Ken Leebow

    Once again, confusion reigns. For the most part, a calorie is a calorie. We’ve got an obesity epidemic and we’re going to worry about the minutia of a calorie?

    It’s very simple; eat whole foods, don’t eat junk food (fast food, processed food and other known junk – skittle, snickers, and snackwells), consume less sugar, and trite but true, eat more fruits and veggies.

    Sure we can divert and confuse people about calories, carbs, fat, and much more … as we play a stupid game and the people on the sidelines keep getting bigger and unhealthier.

    Ken Leebow
    http://www.highsatiety.net

  • http://www.thetableofpromise.blogspot.com The Table of Promise

    Maybe someone should call the Sugar Association and the WHO and the USDA and the CRA and the IOM and tell them that sugar is bad for us on so many levels. For The Sugar Association to claim that it is safe for us to eat 25% of our calories a day from sugar? That is ludicrous.
    Calories are certainly not equal. I am 5’7″ and weigh 133 pounds, just as I did in High School before I gained weight as an adult, and I do it on a high fat diet. What’s my secret? Sometimes I go days without eating refined sugar.

  • http://www.chefmike.ca mike benninger

    WOW!!! Thank you Hemi for such a provocative article!! To hear reasonable adults being able to discuss a national crisis (yes, it’s a crisis) with sane discussion and debate is what FOODUCATE is all about.

    I know a calorie is a calorie in physics class, but all bets are off when we eat it. I know the BIG FOOD lobby would lose their mind, but I see a great PHD thesis here!

  • unstuck

    Like all these anti-carb nuts, they put all Carbohydrates in the same boat. You can’t compare sugar in candy to fibre or carbs in whole grains and fruits – even though they are both “carbohydrates” – in terms of their effect on human metabolism.

    Not all carbs are created equal, in the same way as not all fats are created equal. You KNOW that candy and bacon are junk, c’mon. And you know that carrots and almonds are not junk. Why overcomplicate things? Eat natural, eat fewer calories. Thanks.

  • http://www.nmsociety.org Richard Feinman

    I am grateful for the coverage of this issue but I might add two technical points.
    “Each bite we eat contains a certain amount of energy, regardless of it’s source. 100 calories from fat or 100 calories of carbs is still 100 calories” is not correct. Calories in food are the energy of complete oxidation of the food to CO2 and water. Calories in chemical thermodynamics are for REACTIONS not substances. So, 100 calories is the energy of oxidation in the calorimeter. You do anything else, make protein, make DNA, establish membrane gradients, etc. all bets are off. This is similar to the point in Bill’s post
    Also, chemical thermodynamics is primarily about the second law, that all (real) chemical reactions are inefficient. It would be surprising if processing of all food had the same inefficiency.