TDEE significant drop?

aalhasan

Hello everyone,

Since 1st of May I've been living on a very low calorie diet.
Age: 19
Gender: Male
Height: 5'9
Starting Weight: around 220 pounds
Current Weight: around 177 pounds
Goal weight: 160 pounds
As you can see that's a huge drop (43 pounds in 3 months)

My daily intake has always been around 1300-1500 calories per day, with a couple of "cheat" days per month (1800+)

Now as I'm approaching my goal weight, I'm planning to go for the TDEE - 20% method.

My question is: My BMR used to be around 1900. Is it possible that the BMR/TDEE dropped significantly because I've been living on a very strict calorie intake? Or is the BMR/TDEE independent of the diet type?
Also, what am I to expect when I start eating around 2000 calories after eating around 1300 regularly?

Thanks for your help in advance. :flowerforyou:

SirBonerFart

You're TDEE dropped because you lost 43lbs

3dogsrunning

Yes, eating very low over a long period of time can lower your BMR and your TDEE. Weight also affects BMR and TDEE. Unless you actually had yours tested, the reason why you are seeing this difference is simply your change in bodyweight.

cwolfman13

Your BMR and TDEE are lower because you've lost weight...ergo, your body doesn't require the same amount of energy that it needed when you were heavier. The leaner you are, the less calories you're allowed.

Iron_Lotus

Your BMR and TDEE are lower because you've lost weight...ergo, your body doesn't require the same amount of energy that it needed when you were heavier. The leaner you are, the less calories you're allowed.

Sh!tty but true

heybales

It should have dropped for several reasons that are very valid.

You lost muscle mass most likely eating that little daily.
Less muscle mass - smaller metabolism.

Less muscle mass, less ability to store glucose with required water - that is part of Lean Body Mass just like muscle is.
Less LBM, smaller metabolism too.

You are moving less mass around now, less energy spent daily on moving time.

You likely did slow down your metabolism a tad because of undereating also, unless you were a whole lot wiser on the workout type and protein intake than eating level.

In other words, your BMR/TDEE based on age, weight, height is probably inflated compared to a better estimate based on bodyfat %, which is Katch BMR. Because you have less LBM than expected compared to average healthy ratio.

So careful on figuring out TDEE and less 20%, which should really be 15% at this point, 10% at 10 lbs to go.
You could easily NOT be in an actual deficit compared to what numbers say.
But whole lot smarter starting on the high side than the low side as you've done.

aalhasan

My weight loss has been somehow constant, with very small variations. I'm losing the same amount of pounds per week as I used to 4-5 weeks ago. I guess I've maintained or reduced the loss of my muscle mass well.
I understand that BMR drops when you lose weight but I was concerned about the effect of a very strict diet on it, and as you said it probably drops because of less muscle mass.

So a question arises from here: If I eat close to the "calculated" maintenance rate which might not be true, and eat loads of protein, and lift, am I in a win-win situation? that is, if I'm below TDEE I'll lose weight, and if I'm already above I'll gain muscle?

heybales

My weight loss has been somehow constant, with very small variations. I'm losing the same amount of pounds per week as I used to 4-5 weeks ago. I guess I've maintained or reduced the loss of my muscle mass well.
I understand that BMR drops when you lose weight but I was concerned about the effect of a very strict diet on it, and as you said it probably drops because of less muscle mass.

So a question arises from here: If I eat close to the "calculated" maintenance rate which might not be true, and eat loads of protein, and lift, am I in a win-win situation? that is, if I'm below TDEE I'll lose weight, and if I'm already above I'll gain muscle?

Actually, consistent weight loss when it should have been slowing down when eating the same amount, almost shows it was muscle mass.
Because if your TDEE came down because of moving less mass, that would mean you had less deficit actually in place eating the same amount. Weight loss should have been less and less. So what that means is you kept losing muscle. Considering muscle only provides 600 calories of energy per pound, compared to fat with 3500, much easier to lose a pound of muscle than fat. You lost less at first, more later.
Carbs is 500, so even easier, but that is replaced or almost at next meal. Well, unless constantly in a big deficit carb state, which makes it easier for the muscle burn.

That is the best plan for when you think you might be eating over TDEE.

Because eventually, it won't be, it'll become maintenance level as your LBM and muscle mass specifically increases.

AJ_G

Your TDEE definitely dropped because you chose to go on a very low calorie diet, and you lost a ridiculous amount of weight in a short period of time. While that may look good on paper, such quick weight loss means that a significant portion of your weight loss was muscle, which is not optimal, because muscle mass drives your Basal Metabolic Rate, and since that dropped, your TDEE has dropped.

aalhasan

So what's the best thing to do now in terms of food intake and lifting?

SirBonerFart

Your TDEE definitely dropped because you chose to go on a very low calorie diet, and you lost a ridiculous amount of weight in a short period of time. While that may look good on paper, such quick weight loss means that a significant portion of your weight loss was muscle, which is not optimal, because muscle mass drives your Basal Metabolic Rate, and since that dropped, your TDEE has dropped.

Strong broscience

heybales

So what's the best thing to do now in terms of food intake and lifting?

Best estimates of everything. Still estimates, but a place to use.
In this case though, the recommended is lowest to retain muscle mass, but if you want to take this time to recomp at same time, eat halfway between TDEE and eating goal. Shoving most of those calories in post workout for 24 hrs.

http://www.myfitnesspal.com/topics/show/813720-spreadsheet-bmr-tdee-deficit-macro-calcs-hrm-zones

aalhasan

Thanks for the info. To be honest, I got really scared when I read your reply about how most of my loss was muscle mass. I can't see big differences in my posture and build except that I look thinner and my cloth sizes went down significantly but your explanation about my constant loss makes sense.
I started at around 33% body fat (obese) and I think I'm around 23-25% now which is still considered overweight.
Could it be that because of my obesity, most of the 43 pounds were fat and the muscle loss was minimal?

SirBonerFart

Thanks for the info. To be honest, I got really scared when I read your reply about how most of my loss was muscle mass. I can't see big differences in my posture and build except that I look thinner and my cloth sizes went down significantly but your explanation about my constant loss makes sense.
I started at around 33% body fat (obese) and I think I'm around 23-25% now which is still considered overweight.
Could it be that because of my obesity, most of the 43 pounds were fat and the muscle loss was minimal?

It was mostly fat, don't worry

heybales

Thanks for the info. To be honest, I got really scared when I read your reply about how most of my loss was muscle mass. I can't see big differences in my posture and build except that I look thinner and my cloth sizes went down significantly but your explanation about my constant loss makes sense.
I started at around 33% body fat (obese) and I think I'm around 23-25% now which is still considered overweight.
Could it be that because of my obesity, most of the 43 pounds were fat and the muscle loss was minimal?

Oh, never most, either by pounds or %. But more than you would have liked and more than was needed.

At the start, yes, when you really had a deficit where the math works out for the 3500 cal / lb of fat for energy. But even some then was going to be muscle unless progressively lifting heavy and eating enough protein.

Though even in that case, you don't lose what you use, but your body can start deciding what is used most compared to least.
Muscle breakdown happens no matter what, all the time, diet or not. The amount of diet and exercise and protein just help determine what the body can rebuild again, either all or almost-all.

But as you lost more fat and weight, the amount of almost-all being re-built again would become less and less. So there is additional weight lost, but smaller % from fat.

The type and amount of exercise and protein would really determine how bad an effect.

Lots of intense cardio and low carb diet - goodbye muscle easily.
Lifting only reasonable amount of time and high protein diet - not so bad at all, depending on other stress your body is dealing with.

aalhasan

I apologize for plugging that "most" in my reply. You never said that.
I have been lifting + doing elevated pushups at least 3 times per week and my protein intake has very rarely gone below 60g per day (on the ~1300 calories diet).
You seem to be very well informed on this subject and I would like to get an idea of how much muscle mass I have possibly lost,
Possibly 10 pounds out of the 43 pounds? More? Less?

Again, thanks for the info everyone. I'll work on increasing my intake (specifically protein) and lift. :flowerforyou:

heybales

I apologize for plugging that "most" in my reply. You never said that.
I have been lifting + doing elevated pushups at least 3 times per week and my protein intake has very rarely gone below 60g per day (on the ~1300 calories diet).
You seem to be very well informed on this subject and I would like to get an idea of how much muscle mass I have possibly lost,
Possibly 10 pounds out of the 43 pounds? More? Less?

Again, thanks for the info everyone. I'll work on increasing my intake (specifically protein) and lift. :flowerforyou:

60g may be the RDA minimum for normal diet, but not enough when in a deficit.

Easy method is 0.82 g per lb of weight, or about 1 g per lb of LBM if you have estimate of bodyfat%. Change the goals for macros to whatever % makes those grams happen. Or the spreadsheet spells it out too.

Really wouldn't be able to know for yourself, only it's a whole lot harder building it back up.

Here's study of guys, starting lifting, eating at maintenance, that increased LBM (not just muscle which is merely one part of LBM, they didn't measure for muscle mass specifically sadly, so it would be less than this) at the rate of 3.5 lbs in 16 weeks. Not even a lb a month of LBM, less for muscle mass though some.
http://www.myfitnesspal.com/topics/show/778012-potential-muscle-gain-lifting-and-metabolism-improvement

For myself, trying to pay attention but getting into training for a triathlon too much, lost 2 lbs in 6 weeks of LBM. Considering I was topped off with glucose stores prior to weigh-in day, that was not a loss of just glucose, but muscle and whatever glucose it would have held. So mainly muscle. Lost about 6 lb fat though, so that's good.
And post discovery, I could go back to my records and the 3 bad intense cardio days in a row, and see exactly why it happened. A little week after week. Only 200 cal burned of muscle each week, probably 100 cal worth each day. Adds up.

I was underestimating my calorie burn based on old tests, and so when I thought I was eating enough carbs before the next workout, I was very short. Which means I touched on muscle destroying mode 1-2 days each week easy. So I accomplished what can be done with merely diet.

aalhasan

Thank you so much for taking the time to type all that. Highly appreciated!