The Skeptics Guide to the Universe Forum

Quote from: jt512 on Today at 12:23:47 AM

Quote from: bachfiend on Today at 12:04:43 AMI've just thought of something else:

I'm asking why there's an increasing epidemic (it's getting to be a pandemic with the globalisation of the American lifestyle) of people being overweight or obese.

You're asking what is the best way of treating people when they're overweight or obese.

They're different questions.

I agree that those are different questions and that both are important. But I'm asking neither one. I'm actually not asking any question at all. I'm saying that weight loss is proportional to calorie deficit, and to a very good first approximation, therefore, it doesn't matter whether you create that deficit by decreasing calorie intake, increasing calorie expenditure, or a combination of both. All that matters is the magnitude of the deficit.

QuoteThe study I linked to at the start of this thread wasn't asking about exercise as a treatment.

Nobody cares about that study. We've all moved on.

QuoteI think that there's the epidemic because people are eating excess calories, not that they're expending fewer calories.  People are still expending around 2500 kca per day, but consuming 3000 kcal per day.

I largely agree with that. As I've said before, the largest cause of the obesity epidemic in the US is the portion sizes of our meals that we've become accustomed to. And it's not just in fast food restaurants. It's ubiquitous. We get a lot of visitors from Europe. They all can't believe how large a typical restaurant meal here is.

But lack of exercise is a problem, too. Compared to Europe, we are a very sedentary population.

So the aggressive advertising and marketing of ultraprocessed junk food high in sugars, fats and salt aren't a problem in producing the obesity epidemic?  Sugared beverages aren't a problem?  Industrial bread containing so much sugar that they're more cake than bread isn't  a problem?

Anyhow.  I've just got from the gym.  According to my super-accurate heart rate monitor, I've just expended 1070 kcal, so I now have your permission to have a double cheese burger and large regular coke - when I finally feel hungry after my overnight fast.

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Quote from: bachfiend on Today at 12:04:43 AMI've just thought of something else:

I'm asking why there's an increasing epidemic (it's getting to be a pandemic with the globalisation of the American lifestyle) of people being overweight or obese.

You're asking what is the best way of treating people when they're overweight or obese.

They're different questions.

I agree that those are different questions and that both are important. But I'm asking neither one. I'm actually not asking any question at all. I'm saying that weight loss is proportional to calorie deficit, and to a very good first approximation, therefore, it doesn't matter whether you create that deficit by decreasing calorie intake, increasing calorie expenditure, or a combination of both. All that matters is the magnitude of the deficit.

QuoteThe study I linked to at the start of this thread wasn't asking about exercise as a treatment.

Nobody cares about that study. We've all moved on.

QuoteI think that there's the epidemic because people are eating excess calories, not that they're expending fewer calories.  People are still expending around 2500 kca per day, but consuming 3000 kcal per day.

I largely agree with that. As I've said before, the largest cause of the obesity epidemic in the US is the portion sizes of our meals that we've become accustomed to. And it's not just in fast food restaurants. It's ubiquitous. We get a lot of visitors from Europe. They all can't believe how large a typical restaurant meal here is.

But lack of exercise is a problem, too. Compared to Europe, we are a very sedentary population.

I don't mind generic TV violence, even large battles and mass killings, when it doesn't go in depth on the details. I do mind torture and scenes where they take care to make it about the suffering and the intentions to cause suffering.

Not just for what they're showing, but for what it says about the writers and directors and what they're choosing to make the story about. Especially if they have supposed good guys be involved in it, and not face consequences for it. But even the villains, you don't have to show it, you don't have to go for the shock factor. Implied violence is plenty.

Quote from: bachfiend on September 26, 2023, 11:44:31 PM

Quote from: jt512 on September 26, 2023, 09:40:44 PM

Quote from: CarbShark on September 26, 2023, 05:44:06 AM

Quote from: jt512 on September 25, 2023, 07:48:41 PMSo, to recap. We are now all in agreement that if you are in energy balance, then (1) increasing exercise increases your total energy expenditures, (2) doing that while maintaining your current diet leads to negative energy balance, (3) and that in turn loses to weight loss.

On paper, yes.

Are we all agreed then that in clinical trials where exercise is used by itself as a weight loss intervention it has not found to be effective...

No. When exercise is sufficient in quantity and closely supervised, so that compliance is assured, clinical trials have shown that exercise alone is effective in producing weight loss. Look at these results, for example:



These are results from a 10-month clinical trial in which untrained overweight and obese male and female subjects were randomized either to control (no exercise) or to 5-day-a-week aerobic training, that was progressively increased to either 400 kcal or 600 kcal per session. No dietary advice was provided. All exercise sessions were supervised by study personnel to ensure that the target exercise expenditures were achieved at every session.

Both exercise groups lost body weight and fat and gained lean body mass. Those in the 600-kcal group, naturally, lost more weight and fat than those in the 400-kcal group. There were no significant difference between sexes.

BMR was measured throughout the 10-month study and did not decrease, despite the beliefs of bachfiend, which disagree with the entire literature on the subject.

Except for having to come into the lab for an hour or so 5 days a week, subjects maintained their normal lifestyles. Thus, subjects lost weight despite whatever compensatory mechanisms you, bachfiend, and the other exercise deniers think occurs.

Quote...and where exercise has been used with a weight loss diet it has not been found to be significantly more effective than the weight loss diet by itself?

No, I haven't seen that. What I have seen is that the combination of diet and exercise produces greater effecgts than either one alone, as almost must be the case. Weight loss is proportional to energy deficit.

How do you know that the participants who are making the effort to come into a lab 5 times a week for 10 months aren't making other changes in their lifestyles including diet?

First of all, the investigators monitored diet by multiple means including diet diaries, multiple 24-hour recalls, and direct observation of ad libitum eating, and they found no changes over the course of the study.

But, let me get this straight: you think that subjects randomized to each group changed their diet in proportion to the number of calories of exercise they did. And that that accounts for the results of the study.

QuoteYou have the hypothesis that the intervention participants haven't changed their diets.  Where is the evidence for your hypothesis?

No. You have the hypothesis that subjects changed their diets (and, in fact, did so in proportion to the amount of exercise they were assigned to do). Where is the evidence for that absurd notion?

Apparently, you just believe that calories burned by exercise somehow don't lead to lead to weight loss, and you will go to any ridiculous length to defend that belief. I learned a long time ago not to bother arguing with fanatics. See ya.

I've just thought of something else:

I'm asking why there's an increasing epidemic (it's getting to be a pandemic with the globalisation of the American lifestyle) of people being overweight or obese.

You're asking what is the best way of treating people when they're overweight or obese.

They're different questions.

The study I linked to at the start of this thread wasn't asking about exercise as a treatment.

I think that there's the epidemic because people are eating excess calories, not that they're expending fewer calories.  People are still expending around 2500 kca per day, but consuming 3000 kcal per day.

I think the answer to your question is that overweight and obese people should first change their diet, and also do the exercise they can tolerate, if they can tolerate it, to improve their fitness.

Quote from: jt512 on September 26, 2023, 11:42:23 PM

Quote from: bachfiend on September 26, 2023, 11:10:01 PM

Quote from: jt512 on September 26, 2023, 08:46:56 PM

Quote from: bachfiend on September 26, 2023, 05:05:30 PM

Quote from: jt512 on September 26, 2023, 05:26:52 AM

Quote from: bachfiend on September 26, 2023, 02:51:16 AM

Quote from: jt512 on September 25, 2023, 11:34:35 PM

Quote from: bachfiend on September 25, 2023, 10:27:54 PMAs you become fitter, by exercising daily and after a period, your daily energy expenditure falls back to what it was when you were sedentary because you're expending less energy when you're resting or doing light everyday activities cancelling out the energy expended exercising.

Let's see the metabolic studies that show that, or is that just your hypothesis.

BTW, for you personally, since you do around 1000 kcal/day of exercise, you would have to somehow save 1000 kcal/day somewhere else. Even if you just spent the rest of the day in bed, you wouldn't be able to reduce your energy expenditure that much.

The metabolic studies have already been done, indirectly, using the gold standard doubly labelled water method comparing sedentary and active populations, even of the same ethnic group, so it's not just comparing Americans to San tribes.

Citations needed.

QuoteAnd we also know that training results in less exertion, and less energy expenditure, for the same, or even greate amount of, work performed.

From my heart rate monitor, yesterday I was expending less than 50 kcals per hour.  22 hours time 50 kcals per hour equals 1100 kcals.  Plus the 900 kcals I expended in the gym that equals 2000 kcals, less than the 2252 kcals measured with the heart rate monitor.

I have no idea what you're saying here. Do you mean that had you not gone to the gym, your total 24-hour energy expenditure would have been 24*50=1200 kcal? That would be ridiculous.

One of the options I offered when I reported my energy expenditure using the heart rate monitor (the first time before I'd gone to the gym I'd said that after 11 hours my energy expenditure at rest was coming out at less than 50 kcals per hour) was that heart rate monitors are very inaccurate at estimating energy expenditure, let alone daily energy expenditure, yet all the research on the role of exercise in weight loss relies on heart rate monitors relies on heart rate monitors , and the estimates are regarded as accurate.

Energy expenditures increase nearly linearly with heart rate. The slope of this line is remarkably consistent from person to person. However, the intercept (your resting heart rate) varies greatly from person to person. However, if you know your RMR and your resting heart rate, you can rely on your heart rate to accurately predict your energy expenditures for any heart rate.

Furthermore, because the slope is consistent from person to person, HR can be used to accurately calculate the average energy expenditure of a group. This is because the individual differences in the intercept will average out. For this reason, HR can be used in clinical trials to determine the effect of an intervention on exercise expenditure. This is because the quantities of interest are the group means.

QuoteIt shouldn't be controversial that you exercise for fitness.

It's not "controversial" to me. It's wrong.

QuoteThe authors of the study I cited at the beginning of this thread (people who exercise in the morning are thinner than people who exercise in the evening, who in turn are thinner than people who exercise at midday - I exercise at midday) offered a number of hypotheses to explain their data, one of which was that people who exercise in the morning have a healthier eating pattern, so it comes back to diet, not exercise.  Another one of their hypotheses was that people who exercise in the morning are burning stored fat not recently ingested carbohydrates - which to me seems like nonsense; a calorie is a calorie.

I have to give credit to the authors for admitting that they don't know what the direction of cause and effect is between the independent and dependent variables in their study, or even if they are causally connected at all. Usually, it's more like, "As predicted,..." or "Consistent with our hypothesis...."

References for your claim that heart rate monitors will accurately predict energy expenditure?

This backs up what I actually said (as opposed to what you wrote):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4005766/

I've already linked to this paper.  The authors note that energy expenditure may be under- or overestimated by 500 kcals per day.  If overestimated that would be significant.  Not very accurate.  Or precise.

Quote from: jt512 on September 26, 2023, 09:40:44 PM

Quote from: CarbShark on September 26, 2023, 05:44:06 AM

Quote from: jt512 on September 25, 2023, 07:48:41 PMSo, to recap. We are now all in agreement that if you are in energy balance, then (1) increasing exercise increases your total energy expenditures, (2) doing that while maintaining your current diet leads to negative energy balance, (3) and that in turn loses to weight loss.

On paper, yes.

Are we all agreed then that in clinical trials where exercise is used by itself as a weight loss intervention it has not found to be effective...

No. When exercise is sufficient in quantity and closely supervised, so that compliance is assured, clinical trials have shown that exercise alone is effective in producing weight loss. Look at these results, for example:



These are results from a 10-month clinical trial in which untrained overweight and obese male and female subjects were randomized either to control (no exercise) or to 5-day-a-week aerobic training, that was progressively increased to either 400 kcal or 600 kcal per session. No dietary advice was provided. All exercise sessions were supervised by study personnel to ensure that the target exercise expenditures were achieved at every session.

Both exercise groups lost body weight and fat and gained lean body mass. Those in the 600-kcal group, naturally, lost more weight and fat than those in the 400-kcal group. There were no significant difference between sexes.

BMR was measured throughout the 10-month study and did not decrease, despite the beliefs of bachfiend, which disagree with the entire literature on the subject.

Except for having to come into the lab for an hour or so 5 days a week, subjects maintained their normal lifestyles. Thus, subjects lost weight despite whatever compensatory mechanisms you, bachfiend, and the other exercise deniers think occurs.

Quote...and where exercise has been used with a weight loss diet it has not been found to be significantly more effective than the weight loss diet by itself?

No, I haven't seen that. What I have seen is that the combination of diet and exercise produces greater effecgts than either one alone, as almost must be the case. Weight loss is proportional to energy deficit.

How do you know that the participants who are making the effort to come into a lab 5 times a week for 10 months aren't making other changes in their lifestyles including diet?  That if they're motivated to exercise in a lab that they won't be motivated to change their diet too?

You have the hypothesis that the intervention participants haven't changed their diets.  Where is the evidence for your hypothesis?