CALORIE CALCULATION (BMR)

sealey0418

Hi! 207lbs 5'7 BMR of 1564 (body analysis scan) I currently have my calories set at 1600 seen as I do daily activity equal to +/- 1 hr moderate to intense exercise a day (spin, cycling, 1hr of elliptical, hiking etc...). Average estimated calorie burn of 3000 cal, I am also doing 16/8. A coworker just mentioned to me that she eats under 1000 cal a day and found that mine were alot... She is also a good 4 inches shorter than me and walks daily but no intense cardio...

I know everyone has what works for them and I should be concerned with if what I am doing is working for ME. I would just like some opinions and or reassurance please! lol

Lietchi

Your friend is starving herself and risking her health. The likelihood of regaining the weight she loses is also considerable.

Even your intake of 1600 could be considered low if you actually have a TDEE of 3000kcal. The true test is in your rate of loss: at your current weight, a loss of 1-2 lbs per week is good (it can be a bit faster the first few weeks because of waterweight loss). On paper, to lose 2lbs per week and with a TDEE of 3000, intake should be 2000 per day. But depending on where you're getting your TDEE estimate from, it could be inflated. So keep an eye on your actual results and aim for a loss of 0.5-1% of your bodyweight.

Retroguy2000

Those are all estimates. Nobody knows. Your colleague may have high NEAT. Your NEAT may be lower after intense exercise. IF is irrelevant for weight loss, it's all about your calories in. If you're working out fasted, you may not have the energy to do as good a workout as you could if properly fueled.

BMR is what you'd burn in a coma, so you shouldn't base your CI on that.

If you really think your TDEE is 3,000, I'd suggest start with at least 2,000, and track your weight change like Lietchi said. Ignore the first week which may have more water loss. After that, if you lose 1.5 pounds and your CI was 2,000, then you can infer that your TDEE is 2,750, since that would be a weekly deficit of 7*750.

sealey0418

Understanding that calorie burn is estimated, if I say 2 500 for conservative sake I am still at enough of a deficit. As for the IF yes it matters, no insulin signals allows body to use the body fat stores to make up the difference. This also helps prevent the slowing down of ''metabolism'' since the body has access to those stores so is not ''starving". I do allow myself some extra calories 1x week or so closer to base maintenance when my activity is higher or the occasion calls for it...
So far this is sustainable and workouts have not suffered. I will keep at it, keep active and see Thank you for input!

Retroguy2000

No, IF doesn't matter for weight loss, except as I said it can make your workout worse if you aren't fueled, which is not good.

It's a lifestyle choice to restrict calories. If it works for you, great. It has no bearing on weight loss.

e.g.

https://www.medicalnewstoday.com/articles/intermittent-fasting-no-better-than-calorie-restriction-for-weight-loss

sealey0418

The timing matters... depends on what burning method is switched on. IMO you're fueled if you are carrying 50+ extra lbs you have access to them... but, we'll agree to disagree...

Retroguy2000

Fast digesting carbs before a workout are a more readily available fuel source than breaking down body fat.

I don't know what you mean about "burning methods switched on". If you reduce calories and consume them in a 16 hour window, or 8 hours, or 4 hours, the same total calories will result in the same weight loss. Studies have shown this.

sealey0418

In your article: The group that fasted with a deficit was eating 150% maintenance on eating days (ie: in storage mode)
also the group that fasted but ate 200% on feeding days (therefore mo overall deficit...) still lost a small amount of weight.... 🤷‍♀️
They don't specify what the fat free mass loss was (could be water especially at 3 weeks of study) also no mention of physical activity levels...

AnnPT77

Where did you get the TDEE estimate of 3000? Do you have an especially active job, or something like that? If not, 2500 might be more realistic. It's unlikely IMO that an hour of moderate to vigorous exercise is adding 1000 net calories to your TDEE.**

I'm with Lietchi on the arithmetic: If your TDEE is truly 3000, you'd expect to lose about 2.8 pounds a week eating an accurately-logged 1600 gross calories daily. That would be as averaged over 4-6 weeks, or whole menstrual cycles if you have those. If your TDEE is more like 2500, the expected average loss would be more like 1.8 pounds a week. A good goal would be 0.5-1% of current body weight per week, with bias toward 0.5% unless weight in itself is a medical problem, and one is under close medical supervision for deficiencies or complications.

After several weeks (or at least one menstrual cycle), you'll have a much better reality-based estimate of your TDEE. Be sure to consider your extra calories days in the arithmetic when you reach that point.

I agree that your colleague, if what she tells you is accurate, is riding for a fall. Eating less than 1000 calories daily is unnecessarily punitive for anyone who's not sedentary, older, inactive, and quite petite. Even most people who are those things can eat more and lose healthfully. Fast loss is not only difficult to sustain long enough to lose a meaningful total amount of weight, it increases diverse health risks.

You should lose weight at 1600 . . . possibly faster than ideal.

** 1000 calories per hour isn't theoretically impossible, but it's a reasonably high level of performance. At your current weight, running at an average of about 6.6 mph for a solid hour would likely net close to that.

sealey0418 wrote: »

The timing matters... depends on what burning method is switched on. IMO you're fueled if you are carrying 50+ extra lbs you have access to them... but, we'll agree to disagree...

Mostly what triggers use of one fuel substrate vs. another is activity intensity. It's not really a switch, it's a continuum from mostly fat burned to mostly glycogen burned as the body goes from rest to highly intense exercise. (One can be tested in a sports lab to learn one's personal fuel substrate use. This information can be important for competitive endurance athletes.)

See, for example: https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2022.854451/full

Oversimplifying, during rest or low-intensity activity, we burn mostly fat as a percentage of calories, but we're not burning many calories. During higher intensity activities, we increasingly burn more glycogen (carbs, basically) as a percentage of calories, but we're burning more calories so the absolute quantity of fat burned during high activity may be higher, even though the percent is lower.

It doesn't matter which fuel we burn when, what matters is overall calorie balance. If we burn more calories in total than we consume, our body's going to have to make up the difference somehow, and its first, best strategy is to make it up by burning stored body fat. But we can only metabolize a certain number of calories of fat daily per pound of fat we have on our body, so effectively someone with more fat to lose can lose faster without risking as much loss of lean tissue.

I apparently had 50 pounds of fat to lose, because I lost it . . . eating from shortly after I got up in the morning until very near bedtime, because that's a happier lifestyle for me personally. IF/TRE doesn't suit me. It also wasn't necessary for me in order to lose weight. IF/TRE helps some people stick with a calorie deficit, and if so, that's a benefit. There's still a lot of controversy over benefits beyond that; and it's very evident that many people have lost weight without IF/TRE . . . many people here on MFP, even, not just me.

sealey0418 wrote: »

In your article: The group that fasted with a deficit was eating 150% maintenance on eating days (ie: in storage mode)

Yes, but eating zero on fasting days, anti-storage mode. Bodies don't reset at midnight. It's cumulative calorie excess or deficit that relates to longer-term body fat change.

also the group that fasted but ate 200% on feeding days (therefore mo overall deficit...) still lost a small amount of weight.... 🤷‍♀️

Yes, no overall deficit in theory. It's somewhat common for people who know they're in a diet study, but directed to eat as usual, to change their eating behavior. 🤷‍♀️ is right.

They don't specify what the fat free mass loss was (could be water especially at 3 weeks of study) also no mention of physical activity levels...

3 weeks is short, yes; but it's a long time for water weight reduction to persist in one group only. Participants didn't consent to testing of skeletal muscle, so we don't know. There are other studies, though, suggesting that a reasonably steady supply of protein facilitates muscle mass retention or growth, and alternate day fasting (ADF) like they were doing doesn't really allow a steady supply of protein. You're only doing 16/8, though, and I'd expect the implications of that to differ from ADF.

Unknown

This content has been removed.