Advanced calorie deficits (Fair Warning - long post)

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  • heybales
    heybales Posts: 18,842 Member
    When I say fat is "burned" I really mean metabolized.

    I used glucose and glycogen interchangeably. However, during periods of intense exercise my understanding states that muscles will draw down stored glycogen stores and pull from blood glucose for energy. Your liver will try to maintain blood glucose levels and also generate ketones depending on liver stores of glycogen (which are relatively small). Glycogen is released in your muscles as glucose when needed. You muscles in aerobic conditions will tend to metabolize fat over glucose and this is greatly affected by dietary choices. However, fat metabolization is preferable for many reasons.

    Liver stores of glycogen are not small. It about 10-15 percent of total organ weight and really, along with plasma stores, the primary source for non-muscle organs.

    I believe I've normally seen mentioned 400-500 calories worth, sound right?

    Even compared to what your muscles in total could be holding, again usually seen referenced 1000-2000 total body, it's not a small % either.

    I think it's interesting that if you look at VO2 test graphs for athletes, new, recreational, and pros, the point that fat metabolism in aerobic exercise drops to 50% isn't that high in the span up to lactate threshold, certainly not max HR. Unless you look at endurance athletes, the long endurance guys.

    While it may be preferable or desired by the one carrying the fat, I'd say the intensity that most exercise at is well beyond it being preferred. And that preferred state only really improves with some specific training, which many aren't about to do because it's not good for weight loss (fat-burning myth) - too slow for the time taken.

    Along with this, the final ratio of fat to carb as energy source is only reached after about 30 min, unless you start out fasted and lower intensity. While many do the former of fasted, they likely don't do the latter of easy cardio.
  • EvgeniZyntx
    EvgeniZyntx Posts: 24,208 Member
    When I say fat is "burned" I really mean metabolized.

    I used glucose and glycogen interchangeably. However, during periods of intense exercise my understanding states that muscles will draw down stored glycogen stores and pull from blood glucose for energy. Your liver will try to maintain blood glucose levels and also generate ketones depending on liver stores of glycogen (which are relatively small). Glycogen is released in your muscles as glucose when needed. You muscles in aerobic conditions will tend to metabolize fat over glucose and this is greatly affected by dietary choices. However, fat metabolization is preferable for many reasons.

    Liver stores of glycogen are not small. It about 10-15 percent of total organ weight and really, along with plasma stores, the primary source for non-muscle organs.

    I believe I've normally seen mentioned 400-500 calories worth, sound right?

    Even compared to what your muscles in total could be holding, again usually seen referenced 1000-2000 total body, it's not a small % either.

    I think it's interesting that if you look at VO2 test graphs for athletes, new, recreational, and pros, the point that fat metabolism in aerobic exercise drops to 50% isn't that high in the span up to lactate threshold, certainly not max HR. Unless you look at endurance athletes, the long endurance guys.

    While it may be preferable or desired by the one carrying the fat, I'd say the intensity that most exercise at is well beyond it being preferred. And that preferred state only really improves with some specific training, which many aren't about to do because it's not good for weight loss (fat-burning myth) - too slow for the time taken.

    Along with this, the final ratio of fat to carb as energy source is only reached after about 30 min, unless you start out fasted and lower intensity. While many do the former of fasted, they likely don't do the latter of easy cardio.

    400-600 sounds about right from back of envelope calculation (liver is 1.3-1.5 kg, male, adult, healthy and glucose @ 4 cals/g).

    And yes, I agree with Bales and see issues with the bold stated above, while fat use might be preferable it just does not happen alone, for most people.

    There are really two places where one can get 80%-90% energy use from fat: at rest or at very high duration of low intensity activity (upon muscular depletion of glycogen). But in reality, it's academic. What you use up in exercise is rebalanced from available substrates and various studies have shown that long-term, for the average person, it doesn't really matter.

    Muscle will NOT tend to metabolize fat over glucose in aerobic conditions. It really depends on intensity and duration for any exercise activity that has general duration (say a 20 min run, a zumba class) these will be around half and half. Increase the intensity and one burns more carbohydrates, decrease the intensity and one burns more fat (as a percent of total burn, but less burn overall - also known as: fat burning zone myth). At very long duration of exercise, we can consider fat metabolism to increase significantly but who is running maximal marathons weekly? (Yeah, those long endurance guys, bales mentions).

    I'd like to know what the OP means by "greatly affected by diatery choices". Can of worms territory, right there.

    (...and a nagging voice in my head says - keep it simple - exercise for fitness, not fat burn. Eat at a deficit and balanced for weightloss. Assure variety and macros for performance.)
  • otter090812
    otter090812 Posts: 380 Member
    In to refer back to, thanks!
  • SHBoss1673
    SHBoss1673 Posts: 7,161 Member
    All good debate folks thanks.

    I'm hoping to stay on track here. While the individual talking points of energy usage are important, lets all remember we're talking about functional calorie deficits not theoretical burn rates.

    By that I mean, while it's important to know how some of the individual processes work as a function of the whole (by that I mean our TDEE). I'd hope we try to keep in mind that in the end, at least in this conversation, we're discussing ways to keep a calorie deficit without causing undo issues to the person in question or to make it harder to lose fat for that person.

    I don't want to get to bogged down in the weeds.

    To that end I'll ask this question: Any trainers or nutriton professionals on this thread? Thoughts on practical applications or past client experiences?

    I can tell you that myself, as a trainer, I've turned around 2 different people by simply changing their routine and pointing them to RD's when I listened to their current thought processes and diet. One person was seeing a nutritionist that had literally no credentials and was advising all kinds of odd dietary restrictions such as no lactose (even though the person was not lactose intolerent), no gluten (again no signs of crohn's disease or any type of wheat allergies that I could see from talking to them), and was on a strict, low intensity program of walking with some light running and the elliptical, and was at 1200 calories. I urged her to see a RD, she did, and I gave her 1 day of higher intensity cardio, 1 day of HIIT training, and 2 days of weight training along with her 2 days of light cardio and after less than a month, she was happier, had more energy, and had lost 6 lbs with a 4% reduction in Fat Mass (we had done bod pod testing at the start of the session upon my request and again at the 1 month mark). She was ecstatic as she hadn't lost weight in over a month before that point. She also looked much better and was down a full size in her clothes. At no point did I give her diet recommendations other than to see a QUALIFIED professional. I hate when trainers start giving advice to clients under the guise (intentionally or not) of being an expert in the field, unless they truely are an expert in the field.
  • EvgeniZyntx
    EvgeniZyntx Posts: 24,208 Member
    nvm.

    But since there were a few questions on startvation mode and AT, I'll just suggest this thread:

    http://www.myfitnesspal.com/topics/show/1077746-starvation-mode-adaptive-thermogenesis-and-weight-loss
  • ToxicTinkerbell
    ToxicTinkerbell Posts: 63 Member
    interesting read
  • heybales
    heybales Posts: 18,842 Member
    All good debate folks thanks.

    I'm hoping to stay on track here. While the individual talking points of energy usage are important, lets all remember we're talking about functional calorie deficits not theoretical burn rates.

    By that I mean, while it's important to know how some of the individual processes work as a function of the whole (by that I mean our TDEE). I'd hope we try to keep in mind that in the end, at least in this conversation, we're discussing ways to keep a calorie deficit without causing undo issues to the person in question or to make it harder to lose fat for that person.

    I don't want to get to bogged down in the weeds.

    To that end I'll ask this question: Any trainers or nutriton professionals on this thread? Thoughts on practical applications or past client experiences?

    I can tell you that myself, as a trainer, I've turned around 2 different people by simply changing their routine and pointing them to RD's when I listened to their current thought processes and diet. One person was seeing a nutritionist that had literally no credentials and was advising all kinds of odd dietary restrictions such as no lactose (even though the person was not lactose intolerent), no gluten (again no signs of crohn's disease or any type of wheat allergies that I could see from talking to them), and was on a strict, low intensity program of walking with some light running and the elliptical, and was at 1200 calories. I urged her to see a RD, she did, and I gave her 1 day of higher intensity cardio, 1 day of HIIT training, and 2 days of weight training along with her 2 days of light cardio and after less than a month, she was happier, had more energy, and had lost 6 lbs with a 4% reduction in Fat Mass (we had done bod pod testing at the start of the session upon my request and again at the 1 month mark). She was ecstatic as she hadn't lost weight in over a month before that point. She also looked much better and was down a full size in her clothes. At no point did I give her diet recommendations other than to see a QUALIFIED professional. I hate when trainers start giving advice to clients under the guise (intentionally or not) of being an expert in the field, unless they truely are an expert in the field.

    Agree.

    I think couple of us just wanting to talk to claims of energy sources used. But really, doesn't matter as you mentioned to a balanced reasonable approach.

    As your example shows - higher carb burn activity gave great results, but still some recovery cardio, post meal glucose replacement happens faster, back to normal fat burning state faster. All had great results.

    Those general recommendations always seem to be fine, unless there is real food allergy or sensitivities not figured out yet - unduly stressing the body.

    I've talked to most of the trainers at the gym, just friendly banter discussions, so I've picked up on many of their personal choices regarding diet. And when I overhear them talking to their clients - it's coming out. Unnecessary advice and all.

    Shoot, our spin bike instructor started peppering his post class comments about what to eat that night with his recent conversion to Paleo, because of some guys he runs with. And giving advice on diet in general - no numbers thank goodness.
    And his fitness knowledge is already really lacking - "lets stay below 80% HRmax for this session so we burn all stored-fat, we don't want to go above 80% and start burning carbs you ate for breakfast and lunch" - never mind it 6pm class at this point.

    Ugh.
  • SHBoss1673
    SHBoss1673 Posts: 7,161 Member

    Agree.

    I think couple of us just wanting to talk to claims of energy sources used. But really, doesn't matter as you mentioned to a balanced reasonable approach.

    As your example shows - higher carb burn activity gave great results, but still some recovery cardio, post meal glucose replacement happens faster, back to normal fat burning state faster. All had great results.

    Those general recommendations always seem to be fine, unless there is real food allergy or sensitivities not figured out yet - unduly stressing the body.

    I've talked to most of the trainers at the gym, just friendly banter discussions, so I've picked up on many of their personal choices regarding diet. And when I overhear them talking to their clients - it's coming out. Unnecessary advice and all.

    Shoot, our spin bike instructor started peppering his post class comments about what to eat that night with his recent conversion to Paleo, because of some guys he runs with. And giving advice on diet in general - no numbers thank goodness.
    And his fitness knowledge is already really lacking - "lets stay below 80% HRmax for this session so we burn all stored-fat, we don't want to go above 80% and start burning carbs you ate for breakfast and lunch" - never mind it 6pm class at this point.

    Ugh.

    Ugh, no he didn't! Seriously with the below 80% stuff? I am fine with trainers giving out advice on food types as long as they either have (at a bare minimum) taken and passed nutrition certifications, and/or they at least preface it by saying that they are not a nutrition expert, and if someone really wants to tweak their diet to go see a qualified professional.

    I mean, I've spent 7 years reading studies and completing a masters level course in "advanced nutrition and human metabolism" and I still preface advice with the "I'm not an expert" phrase. Even my GP doctor (who's a very good doctor, I got lucky with this guy" makes that statement before we chat about food. He knows I do training and do a lot of research and we trade ideas once in a while, but he always refers me to their RD in the end if I have more in-depth questions.
  • vyorgan
    vyorgan Posts: 9 Member
    So as not to "hijack" this one, I started a new thread about scientific experiments related specifically to "starvation mode" with responses to some of those papers above (I didn't have time to get through all of them yet).

    http://www.myfitnesspal.com/topics/show/1192992-scientific-basis-of-starvation-mode

    Feel free to post more studies there.
  • yarwell
    yarwell Posts: 10,477 Member
    http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004377

    At 3 month check, sedentary TDEE had dropped by the following amounts, below what the formulas would have indicated for new measured LBM and FM, and SMR. In other words, it lowered the expected amount, and an additional...
    CR - 371
    CREX - 2
    LCD - 496

    I'm not a big fan of the way they use their own small sample correlations for TDEE at baseline for the subsequent projections of "expected" TDEE etc. Hall has done this in papers and ends up with lines that are quite different in gradient to the "standard" large population correlations.

    When you look at TDEE = 1630+33.4(FFM in kg) +1.9(FM in kg) for example in the above reference (I missed off age and gender terms as they are constant) and compare with say Katch-McArdle BMR = 370 + (21.6 x Lean Body Mass(kg) ) the sensitivity to FFM is much higher in their TDEE equation - a multiplier of 1.54 which is more than the TDEE/BMR activity ratio.

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