February 29, 2012

Nutritional Biochemistry

Do calories matter?

Read Time 9 minutes

In a word, yes.  But, technically this is the wrong question.

 The correct question is probably closer to, “What is the impact of the calories I consume on my body’s ability to store fat versus burn fat?

The immediate follow-up question to some variant of this first question is, “Should I be counting calories?” In a word, no. But you’ll want to read this post fully to qualify that answer.

Before I answer these important questions, let’s spend a few moments reviewing five key concepts.

Key concept #1 – the definition of a calorie

A calorie is a unit of measurement for energy content. By formal definition a calorie is the amount of heat energy required to raise one gram of water from 14.5 to 15.5 degrees Celsius at atmospheric pressure.  One-thousand calories is equal to 1 kilocalorie, or 1 kcal for short.    Here’s where it gets a bit tricky.  Most people use the term “kilocalorie” and “calorie” interchangeably.  So when someone says, “a gram of fat has 9 calories,” they actually mean 9 kcals.   The important thing to remember is that a calorie (or kcal) tells you how much energy you get by burning the food.  Literally.  In the “old days” this is how folks figured out the energy content of food using a device called a calorimeter.  In fact, to this day this is how caloric content is measured when doing very precise measurements of food intake for rigorous scientific studies.  As a general rule carbohydrates contain between 3 and 4 kcal per gram; proteins are about the same; fats contain approximately 9 kcal per gram.

[If you’re wondering why fats contain more heat energy than carbohydrates or proteins, it has to do with the number of high energy bonds they contain. Fats are primarily made up of carbon-hydrogen and carbon-carbon bonds, which have the most stored energy.  Carbs and proteins have these bonds also but “dilute” their heat energy with less energy-dense bonds involving oxygen and nitrogen.]


Key concept #2 – thermodynamics primer

It might be a good time, if you haven’t done so recently, to give a quick skim to my previous post, revisit the causality of obesity.  In this post I review, among other things, how the First Law of Thermodynamics explains fat accumulation and loss.  To reiterate, the First Law of Thermodynamics says that the change in energy of a closed system is equal to the energy entering the system less the energy leaving the system.  When we apply this to fat accumulation, it looks like this:


People like me (and others) get a bad rap from folks who lack the patience (or training, perhaps) to actually hear the entire argument through before throwing their hands in the air, waving them frantically, and screaming that we’re violating the First Law of Thermodynamics for asserting the Alternative Hypothesis (more on this below).

Let me be as crystal clear as possible, lest anyone feel the need to accuse me of suggesting the Earth is flat.  The First Law of Thermodynamics is not being violated by anything I am about to explain, including the Alternative Hypothesis.


Key concept #3 – current dogma

Conventional wisdom, perhaps better referred to as Current Dogma, says that you gain weight because you eat more than you expend.  This is almost true!  To be 100% true, it would read: when you gain weight, it is the case that you have necessarily eaten more than you expended.   Do you see the difference? It’s subtle but very important — arguably more important than any other sentence I will write.  The first statement says over-eating caused you to get fat. The second one says if you got fat, you overate, but the possibility remains that another factor led to you to overeat.

If you believe Current Dogma, of course you’ll believe that “calories count” and that counting them (and minimizing them) is the only way to lose weight.

Key concept #4 – the rub

Most folks — but not all — who subscribe to Current Dogma do so, in part, because they don’t appreciate one very important nuance.  In the equation above, explaining the First Law of Thermodynamics, they assume the variables on the right hand of the equal sign are INDEPENDENT variables.

Let me explain the difference between independent and dependent variables for those of you trying to suppress any memories you once had of eigenvectors.  As their names suggest, independent variables can change without affecting each other, while the opposite is true for dependent variables.  A few examples, however, are worth the time to make this easy to understand.

  • The weather and my mood are dependent variables.  When the weather goes from gloomy to sunny my mood tends to improve as a result of it, and vice versa (i.e., when the weather goes from sunny to gloomy, my mood goes from good to bad). In this case the dependence is only one-way, though; my mood changing has no impact on the weather.
  • My countenance and my interaction with people are dependent variables.  When I smile it seems to cause a more positive interaction with the people around me.  Similarly, when I’m having a good interaction with someone I tend to smile more.  In this case the dependence goes both ways.
  • My height (while I was still growing) and my hair length are independent variables.  Both of these variables can change without any impact on each other.

How does this tie into the idea of the First Law? Let’s re-write the First Law with a bit more specificity:

The change in our fat mass is equal to what we eat and drink (the only source of energy entering our system) less all of the energy we expend.


Now let’s be even more specific on the “expend” part of the equation.  We expend energy in four ways: Digestion (all the energy we require to break down food, plus the undigested portions that leave our body); Exercise (everyone knows what this is, but I tend to separate it from daily activity since people really like to focus on exercise); Daily activity (the non-exercise activity we carry out); Basal expenditure (the energy we expend “underlying” any activity – e.g., when you are resting).

Let me clarify something before going further.  There are several ways to enumerate and account for our energy expenditure. I happen to do it this way, but you can do it other ways.  The important thing is to make sure that you are collectively exhaustive when doing so (and mutually exclusive if you want to make your life easier – we call this MECE, pronounced “mee-see”).

The First Law is only valid when you consider ALL of the energy entering and leaving the system (i.e., your body).


Back to the independence versus dependence issue for a moment.  If you look at the equation above, and believe the red box has no impact on the green box, and vice versa, you are saying that energy input and energy expenditure are independent variables.  However, this is not the case, and that is exactly why this problem of energy balance is so vexing.  In fact, the figure below is a more accurate representation of what is actually going on (and even this is a gross oversimplification for reasons I will mention shortly).


What you eat actually changes how you expend energy.  Similarly, how you expend energy changes what (and how) you eat.  To be even more nuanced, what you eat further impacts what you subsequently eat.  As you increase (or decrease) in size, this impacts how you expend energy.

So there are actually a whole bunch of arrows all over this diagram (I’ve only shown 2: what you eat impacting how you expend, and vice versa. If I included all of the arrows, the diagram would get out of control pretty quickly).

I’m not telling you anything you don’t already know, even though it may sound like it for a moment.  When you exercise your appetite rises relative to when you don’t exercise.  When you eat a high carb meal you are more likely to eat again sooner compared to when you eat a high fat/protein meal due to less satiety.


Key concept #5 – the Alternative Hypothesis

If, like me, you don’t subscribe to Current Dogma, you’d better at least have an alternative hypothesis for how the world works.  Here it is:

Obesity is a growth disorder just like any other growth disorder.  Specifically, obesity is a disorder of excess fat accumulation.  Fat accumulation is determined not by the balance of calories consumed and expended but by the effect of specific nutrients on the hormonal regulation of fat metabolism.  Obesity is a condition where the body prioritizes the storage of fat rather than the utilization of fat.

Why is this different from Current DogmaCurrent Dogma says it doesn’t matter what you eat, it only matters how many calories that food contains.  If you eat more calories than you expend, you gain weight.  The last part is true, but the first part is not. The Alternative Hypothesis says it DOES matter what you eat and for reasons far beyond the stored heat energy in the food (i.e., the number of calories).

Let me use an example to illustrate this.  Consider the following table of various substances known to contain a lot of stored energy.  The table shows their energy content in units we usually use to describe energy density, kilojoules per gram (middle column), and I’ve converted to units we typically only use for food energy, kcal/g or “calories” per gram, (right column). [Here we need to be very clear to distinguish between a technical calorie and a kilocalorie, which is almost always what we mean.]  A kilojoule is about 240 calories (not kilocal), so 1 kj is about 0.24 kcal, and therefore 1 kj/g is about 0.24 kcal/g.

I’ve highlighted, in bold, four rows of things we typically eat: fat (olive oil, to be specific) with about 8.9 kcal/g; ethanol with about 7.0 kcal/g; starch with about 4.1 kcal/g; and protein with about 4.0 kcal/g.

I’ve also included in this table some other substances known to contain chemical energy such as liquid fuels (e.g., gasoline, diesel, jet fuel), coal, and gunpowder.  Hard to imagine a world without these chemicals, for sure.

A quick glance of the table, which I’ve ordered from top to bottom in terms of caloric density, would suggest eating olive oil would be more “fattening” than eating starch since it contains more calories per gram, assuming you subscribe to Current Dogma.

But that same logic would also suggest eating coal would be more fattening than starch and gunpowder less fattening than ethanol.   Gasoline would be more fattening than jet fuel.  Hmmmm.  Anyone interested in testing this hypothesis (personally)?  Despite my wildest self-experiments, this is one self-experiment I’ll pass on.  Why?  Well for the same reason you’d pass on it – you know that there are far more important consequences to drinking diesel or snorting gunpowder than their relative energy densities.


Sure, everything on this list is an organic molecule largely composed of the following four atoms: carbon, hydrogen, oxygen, and nitrogen.  Not to bore everyone with a lesson on organic chemistry, but it’s the actual bonds between these atoms that are responsible for their energy densities.  When you “liberate” (i.e., break) the bond between an atom of carbon and hydrogen, for example, you release an enormous amount of stored chemical energy.  This table tells you exactly how much energy you would release if you were to break the bonds in these molecules, but that’s all it tells you.  You can’t actually know, just by looking at this table, if jet fuel is more paraffinic than diesel or if gasoline has more isomerization than propane.  And, you certainly have no idea, from the information contained in this table, of exactly how each of these substances will impact the hormones, enzymes, and cell membranes in your body if you ingest them.

Is it relevant to our bodies that olive oil has about the same energy density (i.e., calories) as biodiesel (also known as fatty-acid methyl-ester)?  Or, is it more relevant to us that consuming olive oil has a very different effect on our bodies than consuming biodiesel beyond anything to do with the calories contained within them?  Obviously consuming equal caloric amounts of olive oil versus biodiesel will have a very different impact on our body.  Why then is it so hard to appreciate or accept that equal caloric values of olive oil and rice could also have very different impacts on our body?

The upshot

Let’s get back to the question you actually want to know the answer to.  Do calories “matter”, and should you be counting them?

Energy density (calories) of food does matter, for sure, but what matters much more is what that food does in and to our bodies.  Will the calories we consume create an environment in our bodies where we want to consume more energy than we expend?  Will the calories we consume create an environment in which our bodies prefer to store excess nutrients as fat rather than mobilize fat?  These are the choices we make every time we put something in our mouth.

Our bodies are complex and dynamic systems with more feedback loops than even the most elaborate Tianhe-1A computer.  This means that two people can eat the exact same things and do the exact same amount of exercise and yet store different amounts of fat.  Does it mean they have violated the First Law of Thermodynamics?  Of course not.

Similarly, genetically identical twins can eat different macronutrient diets (i.e., differing amounts of fat, protein, carbohydrates) of the same number of calories, while doing a constant amount of exercise, and accumulate different amounts of fat.  Does this violate the First Law of Thermodynamics?  Nope.

What you eat (along with other factors, like your genetic makeup, of course) impacts how your body partitions and stores fat.  In case anyone is wondering how I got over 2,000 words into this post without mentioning the i-word, wonder no longer.  Insulin, while not the only factor involved in this process, is probably at the top of the list. When you eat foods that have the double whammy of increasing insulin levels AND increasing your cell’s resistance to insulin, your body prioritizes fat storage over fat utilization.  No one disputes that insulin is the most singularly important hormone for causing fat cells to accumulate fat.  Somehow the dispute centers on what causes people (full of billions of fat cells) to accumulate fat.

All calories are not created equally:  The energy content of food (calories) matters, but it is less important than the metabolic effect of food on our body.

Photo by Aaron Barnaby on Unsplash

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  1. Brilliant – I was smiling at the end.
    I have always done a decent amount of exercise. Having put on a stone over the past year, yes I know to increased calories, although with the increase of cycling, up to 200 miles a week…. still the fat gain.
    Having lost weight before on low carb regimes, they do work, but I have always noticed I seem to get more energy and less lethargy from fats; ie Avocado… suggesting this to people, brings you back to ‘oh that’s really fattening’…. Hmmmm I can honestly say I’m looking forward to this little food intake change and to see what happens over the coming months !
    Although…. what do I do on the cycle club run cake stop ?!

  2. Peter,

    I find your postings, blogs, writings, etc, fascinating. I know nothing about most of it. I’m just a 52 year old chauffeur with chronic lower back pain that happened upon your site in search of a connection between diet, my back problems and anti-inflammation. A little weight loss wouldn’t hurt either. As I have concluded after reading a lot on the subjects over the last several months, the low-carb or now the very low-carb diet seems to be garnering more authenticity. What makes your work so interesting is the technical, actually very technical, explanations. I look forward to reading more from you in regards to eating for overall good health! Oh, and your children are adorable.

    Thanks again,


  3. I agree with every thing you say but I cannot for the life of me figure out why my girl friend who I love dearly eats a very high fat low carb diet and remains 45 pounds over weight .

    • Very frustrating for her, I’m sure, but unfortunately not that uncommon. More so in women than men. I think about this phenomenon more than most others, but commenting on it thoughtfully is beyond the scope of a comment/response.

    • I just found this site and am hoping to find some answers for the same issue. I’ve tried paleo, keto, AIP and others and still am having a heck of a time keeping the weight off. Maintaining is a very careful balance and some days it works and some days it doesn’t. I cannot figure out what is keeping me about 25 over my goal weight either! 🙁

  4. Just completing 22 months on a very low carb diet (aiming for 20 gm a day). Initially lost 20 pounds in the first 2 months, then stalled, treading water around 211 pounds for 20 months. As you say, very frustrating. Early on I was using the inexpensive urine strips that never (maybe once) showed any ketosis at all. Very frustrating. Two months ago I got a Ketonix breathalyzer from Sweden. It shows I am everyday in the red (high) or in the yellow (medium) range of measured acetone in my breath. Everyday. Surprising. If the Ketonix is accurate, I’m in ketosis every day since I started using it 60 days ago. Wow. But, no budge on the weight.

    I first became obese at age 6 way back in 1954 after a bout of Scarlet Fever. Consequently, I’ve spent 60 years dieting, often very successfully, but still the life long pattern is gain, lose, gain more. I was at a lifetime high when I started this latest iteration of dieting. About 6 years ago I had tried the low-carb diet and in about 4 months lost 60 pounds, which is why I went back to low-carb this time, but as I said, this time very different at only 20 pounds lost in 22 months. Very frustrating.

    My hope is that the other benefits of low-carb are still happening even without weight loss. At 67, my blood measurements are good, and I don’t take any prescription meds. So, that alone is encouraging me to stay low-carb. My family is riddled with diabetes (from way back, long before it became epidemic). All four grandparents, one parent, and now my younger brother developed (old-age) diabetes. So far, I’ve no signs of it. My GP scolds me for asking about it at every visit. But at my age, weight, and family history, I don’t see why diabetes won’t suddenly develop.

    In 2005, I developed symptoms of a blood disease that causes lymphocytes to over-produce a protein, that then thickens the blood. I’ve been treated with monoclonal antibody infusions for the past 4 years, and eating low-carb for the past, as I say, 22 months. At every visit, I remind my hematologist that I’m eating low-carb. He nods and notes that my blood measures, other than the viscosity, are good. I am hopeful, from my readings, that low carb is better for proliferative diseases, than high carb would be, even if only marginally. What is it they say, feed a fever, starve a cold?

    In the last 9 months, my nose-bleeding episodes have stopped (holding breath, as it could be just a pause). Nice, and now if I could just lose some weight, it would be so nice.

  5. Hi Peter –

    I have recently changed the way I exercise, and was looking for information on how weight training can affect Resting Energy Expenditure. I came across this article which makes the case that high-intensity interval resistance training (weights) results in higher REE than traditional weight training. Evidence from my N=1 experiments seem to confirm this work.

    Best regards.


    Cite this article as:
    et al.
    High-Intensity Interval Resistance Training
    (HIRT) influences resting energy expenditure and respiratory ratio in
    non-dieting individuals.
    Journal of Translational Medicine

    • Hey John K

      Are you using the Doug McGuff Method of HIT ? If not , which one? I am in the process of changing my workout routine also. How long are you going between HIT workouts? Do you do split sessions? ( Arms one day , leg another ,etc) Do you engage in other sports or lighter workouts in between HIT?
      I am especially interested b/c I am a primary doc. The more I can confirm the value of HIT the more I can recommend to others. I reviewed the Paoli paper and as a scientist I can tell you it looked weak and full of holes to me.

  6. @AstroSamantha tweeting about leaving the milk unopened in space made me wonder: Is there not precise nutritional intake/body compositional results available from NASA? Weightlessness may confound things but surely they are worth a look at, no?

  7. Hi Peter,

    I have been following you from a month or so ago and I can definitely say you have impacted my life, thanks a lot for the work you have been doing.

    I want to share what I’ve been doing the last month which seems to fit perfectly that diagram of (what we eat – Digestion, exercise, daily activity and basal expenditure) WITH the arrows.

    First of all a little background, I have lost 50lbs in the last year and a half by the conventional method of exercising and “eating better”, by accident that “eating better” was actually a gradual reduction of carbohydrates (but still avoiding fats so I was consuming lots of protein and my carbs were coming from fruits). My transition was very similar to yours and that’s why in the last month when I started nutritional ketosis, it did not affect me that much (didn’t get the “keto flu” symptoms)

    Now here is the interesting part. From 40% body fat (aprox) I have reached 23% (before nutritional ketosis). In the last 3 full weeks of me being in ketosis, I have maintained my routine of lifting weights and playing tennis (notice that all my activities are very anaerobic) During those 3 weeks, I lost 5lbs in the first week (water retention) and then I just got stuck and did not see any fat loss. I was eating whenever I was hungry and was not restricting my calories purposely. During that time I was consuming approximately 2,600kcal per day which means I was eating at maintenance.

    Here is where it gets more interesting. I thought that maybe even though I was in ketosis, my body was not using ketones that much (due to me doing mostly anaerobic exercises) so the only thing that I changed was include a daily fast walk before my first meal of the day for 40 mins. Not really sure if I was at the sweetspot of where my body would love ketones, but I may have been pretty close.

    To my surprise, the last couple of days of me including these fast paced walks, I can go longer without eating, I am simply not hungry for a longer time. Does this mean that I needed to do these walks to teach my body to use the ketones? Maybe for the previous weeks I was in ketosis but my body was not using them at all? (or very little)

    It’s amazing how your depiction of the arrows came into play here… included a more aerobic exercise and now I want to eat differently than before. My hunger was suppressed for so long that I couldn’t even hit my minimum protein target per day to avoid muscle mass and that is the only thing I am going to be very careful about from now on with this change. I am excited to see what will happen in the next few weeks. I will keep doing this walks and keep my anaerobic exercises as well and make sure I am getting at least 1.5g of protein per kg of body mass.

  8. I violate thermodynamics all the time. I am eating between 3000-4500 food calories per day with a macronutrient split pretty close to 50% carbs 30% protein 20% lipids and I only weigh about 140 lbs with a 5 foot 9 inch frame. I can see my abs no problem.
    Exercise? 10 minutes of low intensity stairs to warm up, then five sets of five squats, five sets of five deadlifts, and that’s about it. The rest of the day I sit on my fat–I mean I sit on my skinny ass. I’m actually trying to gain weight though. I make sure to top off my blood amino acid levels every 2 hours with 20-25g protein and eat a salad every day with the rest of my meals for more micronutrients (especially folic acid since it’s required for cell division). I’m an om-nom-nomnivore who enjoys meat, fish, rice, potatoes, vegetables, and milk. I kinda like beans but they digest too slowly for me to realistically get enough calories in my day, even in spite of all the fiber they’ve got in them.

    All of which brings me to a question that I wonder if you can answer: how much of a calorie-sink is it to grow facial and bodily hair? If I were to destroy a bunch of hair roots (e.g. electrolysis) how much closer would I get to positive energy balance, and what are the physiological and social consequences of doing so?

  9. Great information. My question was not answered though and I’m hoping it’s a simple one to answer…most of my life I have been overweight…after marriage, 3 children and age hit me, I became clinically obese. After embarking on Isagenix, I have lost 25 lbs and a ton of inches. However, the plan is a stickler for 1200 calories per day, mostly protein, and I am having a very tough time getting 1200 calories in. I have always been the type of person that can go a whole day without eating and still feel ok. Maybe that’s why I have always been overweight. I am told if I do not consume at least 1200 calories a day my body will store, store, store fat. I’ve found that I’ve plateaued in my weight loss after a month and a half and I still have more to lose. So, my question is this, if I put something in my mouth every 2 hours or so, ie: rice cake with hummus, 1 slice of Ezekiel bread with almond butter, will my body still see it as being fed and continue to metabolize or do I have to stick to at least 1200 calories a day?

    Thanks for the advice!!


  10. Dr. Attia,

    Does consuming BCAA supplements kick you out of ketosis by gluconeogensis?


    Mike J.

  11. Discovered your site reading about UCAN. Very informative! I’ve got my head chopped off making some similar statements you have made on myfitnesspal including breaking laws of thermo and believing in unicorns. I appreciate the complexity you go into. I have a B.S.M.E. and a M.S.E.E in cotrol theory and am very familiar with dynamic systems, feedback loops, and non-linearities. I don’t know physiology though and you site helps.

    One thing I haven’t seen you discuss yet is effects of saturation and rate limiting of the processes you describe. All real systems have these limitations. If you eat big meals, you absorb less than if divided up into smaller meals. That is the hypothesis.

    I’m on a 21:3 IF diet and have lost 38 lbs in 23 weeks (more like 21 weeks since I relaxed diet over Christmas holidays). I want to get a keytone meter to see how much keytones I’m producing. Trying to get back to running (ex 800m track guy in college). Age 54, sw 252, cw 214.


  12. Seems like your saying that:

    A calorie surplus is a necessary condition for fat storage but is not a sufficient condition.

    A calorie deficit is a sufficient condition for fat burning but may not be a necessary condition. As time progresses,, the body will adjust and a person will not be able to continuously keep a calorie deficit to lose weight.

    Did I get it right!? Thanks.

  13. For me personally, if I don’t get 2500 or more kcals per day, then I start to feel it. Seemingly it doesn’t matter how active I am, any less than that and I’ll start to feel really exhausted. Mind you I’m currently suffering from some level of adrenal burnout, probably phase 3, so I’m sure my required calorie intake is affected a lot by this!

  14. My husband has the opposite problem as me! He is currently trying to gain weight and bulk up by upping the calories, protein, and weight lifting. It doesn’t seem to help, however. Do you have any reliable resources you could point me to to learn more about what kinds of foods and eating ha bits will help with this? I love the article. It makes clear that simply counting calories t is not an effective way to gain or lose weight!! And personal experience attests to this.

  15. Excellent blog, Dr. A. I’ve been on a ketogenic diet now for about a month and a half. I have quite a considerable amount of weight to lose and so far I love the keto lifestyle. As I never was necessarily a great lover of sweets and other carbs (although I could certainly destroy a nice warm homemade sourdough bread) it hasn’t been particularly difficult for me to maintain an extremely low level of carb intake, generally less than 10 grams per day. The carbs that I do ingest come from leafy greens and some cruciferous vegetables. I do have a couple inquiries if you could indulge me. I have never had to take blood glucose levels as I’m not diabetic. My brother, however, is. I happened to be present last week when he took his glucose level and I asked him if he wouldn’t mind if I tried it. I had been fasting at that point for approximately 12 hours. To my consternation and amazement my blood glucose level was 35mg/dl. I was in such disbelief that I used a control test sample to make sure the meter was calibrated properly. Tested again at 37. Went out and bought my own meter to keep tabs. I felt absolutely no ill effects whatsoever. In fact, I felt quite well. In the following days my glucose level resolved slowly and now hovers around 70-75 fasting, a tad higher after a meal. Any hypotheses on what caused the abnormally low levels? I thought perhaps an insulinoma, but my insulin levels came back as quite low (can’t recall the exact value at the moment). Another question, because of my ultra low carb intake, many days zero, do you think that a higher protein to fat ratio would be prudent, to allow for slightly higher gluconeogenesis in the absence of carbs? Thanks for the great service that you provide in disseminating knowledge of a field that can be maddeningly convoluted, complex and seemingly ever-changing.

  16. This was very informative and I have taken away that genetic makeup can also effect a person’s weight, because of the way their body deals with fats, or that Current Dogma doesn’t even worry about what it is that you eat but that is all about the calories. I also never knew in order to be considered a calorie it has to raise a gram of water one whole degree. I always though for something to be considered as a calorie it just had to have energy.

  17. hi peter, I am a student from cod.
    The 3 main take away that I read from your article are how when someone says a gram of fat has 9 calories, they actually mean 9 kcals. I didn’t know that it was very interesting thing to read.
    the second main take away is about the twins, how they eat the same thing but have different calories. Its really mind blowing. The 3rd main take away is Fats are primarily made up of carbon-hydrogen and carbon-carbon bonds. very interesting thing to read.

  18. Hi Peter,
    I’m a student at COD. the 3 main points I got from this article are that your body can expend only so much and if you eat more calories than your body can expend, you end up gaining weight. The second thing is that what you eat actually changes how you expend energy. The third thing is that every one accumulates different amounts of fat, and is very interesting to see that this can also happen to identical twins.( who are technically the same person)

  19. Hello, my name is Jalen Gilmer. I am a student at COD, going for a fitness certificate and trying to be a personal trainer. The main 3 things I learned are if I’m going to be always exercising, I shouldn’t eat less because I have a fast metabolism. I also learned that if I have a bad diet, all the exercising and activities I do will go to waste. I also learned that people with large frames trying to maintain a healthy weight should eat a lot of calories, healthy ones though. Thank you for the advice, I will use this as a tool in my journey.

  20. Hi Peter!
    I’m posting a question here, because I can’t find the direct e-mail, i do apologise… As a working m.d., that was thought the dogmatic “low fat, long life” principle, and I’m slowly chewing through the twists and turns in the medical literature in the last 5-10 years concerning metabolic syndrome, fructose, exercise, cholesterol and obesity. And frankly I’m amazed how could all those poorly conducted or so heavily biased studies ever be a baseline for medical recommendations pre 1980s. The main reason I posting here is because I can’t find any relevant data to answer my questions, and I’m wondering do you, as a master in this field, have any in your sleeve. I would die to know:
    1. Do people on a high calorie (but sucrose or HFCS free) diets still get liver fat accumulation or fatty liver disease?
    2. Do people on a high fat, high calorie diet increase their subcutaneous fat, (if eating more that their RDI, or eating until not hungry any more).?
    2. If the answer to previous 2 is no – is it possible that high fat diet is self limiting (calorie-wise) on the visceral transporter – is there any data to support that?
    3. One thing I’m sure about cholesterol (and/or lypoproteins) is that I don’t have any clue anymore what the exact role and transport mechanisms of all branches of cholesterol carrying vehicles are…:-) The exercise is known to raise HDL – which mechanism do you think is most likely behind this?
    4. As an extreme case – do you think it’s possible to reverse the effects of metabolic dysfunction just with the diet alone, with no physical exercise, or in extreme cases with keeping a sedentary lifestyle (<1,5 MET)? (don't get me wrong, I work on an "exercise prescription for health" project, but since I'm throwing away a lot of learned stuff, why not challenge my on field too.
    4. You've reduced your amount of body fat significantly – the common preaching is that the amount of fat cells you gain during your fat years could never be reduced, supposedly we just shrink their size – have you any ideas how did it go with you on a ketogenic diet – did you get less fat or less fat cells?
    5. what's the most practical method to assess insulin resistance?
    6. I can't seem to loose the bad feeling that we're doing the same with sodium in hypertension as we did with cholesterol (daily fat intake) and CHD – the problem I see, but can't find any studies, on it is a cascade reaction to other minerals…Do you have any studies backing up sodium cascade? Maybe the majority of the hypertensive effect comes from fructose toxicity after all as suggested by prof. Lustig…
    7. prof. Ron Moughan did a great presentation on the history of low carb vs high carb diets in physically active people, and the story goes remarkably back (pre 1900). There seem to be some sort of consensus that a HCHD requires lower oxygen cost than a HFD. But your ketogenic diet, or better BHB experiment suggests that the oxygen cost is even lower than that of HCHD? with 1l we get 4,7 kcal when burning fat or protein but 5.1 kcal when burning CH – what's the number then for BHB?

    Thank you for your answers, your time, your openmindness and self experiment data sharing. Greeting from Slovenia.

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