What happens to the fat?

1.
My question is won't I be able to convert my fat to muscle?

2. Will I struggle to gain muscle if I eat below my TDEE?

Maybe someone with a more scientific brain than mine can explain what happens when fat stores are broken down. I was hoping they would be broken down and go to feeding my muscles...but maybe not...

1. no. muscle and body fat doesn't not convert. Either the fat and the muscle cells grow bigger or they shrink. You will never have more or less fat cells and muscle cells than what you currently have. You can make them shrink or grow. Fat cells shrink when you deplete them of the energy stored in them. They provide the body with energy in the form of triglycerides / fats. Fat cells grow when you have excess calories consumed. Muscles grow via insulin + amino acids + proper exercise. Muscles shrink via too much insulin + too much cardio + improper diet + too little exercise.

2. not if you eat complete proteins at every meal and have a proper diet. otherwise, yes, you will have a hard time gaining muscle if you are eating below your Daily Calorie Expenditure improperly. Feed the muscles the amino acids they need. That's all.

3. Body fat stores are broken down only when you are at a calorie deficiet AND are exercising properly. I.E. fat burning mode. Many people don't understand that improper exercise and over exercising can tear down muscle. So can a bad diet.

- happy training
Coach
Teresa, CPT

For a more scientific answer :

Fat cells, scientifically called adipose tissue, store excess energy as tryglycerids. Those tryglycerids can be used by the body as fuel with a metabolical pathway called beta-oxydation, which converts the tryglycerids into acetyl-coa which can then enter the Kreb's cycle (this is the primary pathway to produce energy). This is really a short version of what really happens, but it can answer your question of what happens to you fat storage.

Why you can't use the energy created by the beta-oxydation of your tryglycerids to produce muscle is a bit trickier to answer. Your body has two main "state", anabolic (build things) and catabolic (break down things). Lots of hormones control which state your body is in. Those hormones generally have an effect on your body has a whole, and not just your muscle for example. So if you are in a calorie deficit, your body will create hormones that tell your body to be in a catabolic state to save a maximum of energy, and to not use too much of your reserve.

Please note that weightlifting while in a calorie deficit is great to minimise muscle loss, since weightlifting (or exercise as a whole) does promote hormones that will try to minimise this muscle mass. Please note that this is also a gross oversimplification of a really complex system.

Hmm...so do I have to make a choice between muscle gain or fat loss? Being a greedy human I would like to lose fat and gain muscle at the same time...any ideas?

you can't

You can gain in strength without being on a surplus though since you can gain strength without building more muscle.

Very pertinent bit here, and I can personally attest to this as I gained a substantial amount of strength all around in 2011, during which I was mostly working in slight deficits.