I've been thinking about this. If I am always in a calorie deficit trying to lose weight, how would it be possible to build muscle?
Seems like I could strengthen the muscles I have, but would there really be enough extra calories to actually build?

In the past four weeks, I have lost 7 pounds per the scale. Per 9-point calipers, I have lost 9 lbs of fat and gained 2 pounds of muscle.

So, yes.

I have been weight training 3 X wk with a personal trainer, doing HIIT 3 times per week, and following a high protein nutrition plan.

I did too.

I work out 6 days a week for a total of 9-12 hours, 3-4 hardcore strength sessions, plus cardio and core work.

I have lost ~40 lbs and gained 10lbs of muscle.

The only thing is, I wonder about you doing a caloric deficit. My trainer taught me to fuel my workouts. So for instance, I figured out my BMR (approx) add how many calories I burn from daily activities, then subract 300-500 calories. Add in a high fat, medium protein, low carb diet and I lose 10lbs a month but feed my muscle. He taught me low cal is just a way to rob the body of a healthy metablism (and is the cause of yo-yo ing). Not everyone I share this with buys it, but it works for me.

My experience has been the same as Meg's and midwife's. A seasoned lifter usually has trouble building in a caloric deficit, but you certainly can for quite a while.

Mel

From what I've gathered from talking to various people the more unfit you previously were the easier it is for your body to adapt muscle even while losing weight "Beginners Advantage" or something like that.

I've gained a whole lot in the past year but it really started to increase with running for some reason maybe cause I'm hauling so much weight around. Running isn't usually though of as a muscle builder.

If you have a ton already though I hear it's better to go through cycles of building and weight loss.

Ironic. As I understand, running is a muscle "stealer"!

Typically yes, but I can only go by what changes I've felt in my own body. I was working out previously since May, but once I started running I gained a really solid feeling base.

It's been a pretty dramatic change in the legs/core in the last 3 months. Although I do bike too so it's probably a combo effect.

Husband even hugged me the other night and said I felt "solid" heh.

Nice!!

As I understand it, by weight training your body creates tears in the muscle so the calories you DO intake have to go towards repairing these tears and strengthening them for the next time you work out. It's called calorie partitioning and that's why weight training is so beneficial...you don't use muscle as a source of fuel since you're in a calorie deficit, you use sugar and fat... And of course, by maintaining your lean muscle mass (or even increasing it) you keep your metabolism elevated for longer and burn more calories in a resting state.

This may be a silly question... but how exactly do you measure pounds of fat lost and muscle gained? Someone mentioned a caliper...?? *totally clueless...*

There are different methods pengy. The 3 most common are:
1. Skin fold calipers using a device that looks a little like something you used in geometry class. It has little "legs" in which you measure skin folds to determine the amount of fat under the skin.

2. Biolectrical impedence. You may have seen different scales or hand-held devices. It is based on the hypothesis that tissues high in water content conduct electrical currents with less resistance than those with little water (such as fat tissue).

3. Under water weighing.

Under water weighing is the "gold standard," but it is expensive and not easy to find. Skin fold calipers, if used by someone who is trained to use them properly and accurately is the next best option. Biolectrical impedence is the most convenient and easy to do by yourself but it is also the most inaccurate. However, it is the trend that a person should really be concerned with and even biolectrical impedence will show that. However, care should be taken to take the measurement at the same time, under the same conditions, whenever possible to eliminate some of the potential errors caused by hydration levels and the like.

Pengy, most gyms offer body fat testing (either calipers or bio-impedence). I get mine checked every few months at the Y--it's free with my membership and $5 for everyone else.