Is it true you can't build muscle while eating at a calorie deficit?

No it's not true for a calorie deficit that is reasonable. It is true of crash diets though. Which is why MFP helps us set a healthy weight loss level...so you keep the muscle you have and can actually develop additional muscle strength whilst losing fat and weight.

A deficit of 1280 per day is very high. If you're seeing more definition, it's because the fat is melting away leaving behind the muscle BUT at such a high deficit you may be losing muscle as well which is not good because you will be more prone to sports injuries. There are some real experts here who I am sure will comment too. But I'm sort of doubtful anyone can build muscle on a deficit of 1280/day.

It's pretty much true. There are going to be exceptions and there are specific requirements (it's not easy peasy). If you are very out of shape, follow a progressive lifting program, meet protein needs and have a small(ish) deficit.....it's possible. Women add lean muscle very slowly even at a surplus of calories.

Instead what is more likely - you had a layer of fat covering lean muscle mass. Losing 45 pounds (congratulations!) has eliminated that fat layer, so your muscles are now visible.

Do you eat AT 1280.....or is 1280 a reduction from your TDEE? If it's a reduction of your TDEE - no way you added lean muscle mass (pretty steep).

obese beginners new to lifting can make newbie gains... are you following a progressive lifting program? Then again, on those calories I doubt so. Either way, shedding fat will definitely expose them more, they've always been there you know, carrying around your bones and such lol

You can build muscle while eating at a calorie deficit if you have excess fat remaining that you need to lose, and adequate vitamins & mineral intake.

The muscles don't much care where the building blocks the blood delivers come from--food or fat--so long as all the necessary blocks are present.

If you are already at a body-builder competition fat percent, you have to eat to build muscle because you don't have enough building materials on-hand in your fat stores.

Macy9336 wrote: »

Here is an article about setting a deficit.
http://www.burnthefatinnercircle.com/members/What-is-the-ideal-calorie-deficit.cfm

It explains how obese/overweight people will lose 100% fat, but as you get leaner you start also losing muscle when you lose weight. Good discussion on setting your calorie deficit based on a % of your maintenance level.

Macy, is this 100% fat loss while lifting, or just with a deficit?
I apologize for my ignorance as the posted article asks for a login, which I do not wish to create.

Could just be the weight loss that made your arms look different.

From my personal experience tho the first time I started dieting(also started lifting at the same time) and I was much stronger at the end of my diet than I was at the beginning. I feel the "noob gains" plays a role in this. Comparing it to now when I cut after bulking I lose strength.