Whether you're training for an event, trying to increase your muscle mass or just want to get in better shape, your body relies on three main nutrients for fuel. Because your body can break down carbohydrates, muscle and fat for energy, understanding the order of nutrient breakdown can help you save or build muscle mass and increase fat loss.

Fat Preferentially Metabolized
When glucose and glycogen are not available, your body preferentially breaks down fatty compounds known as triacylglycerols which are present in adipose or fat tissue. Because fat is a high-energy source with nine calories per gram, fat provides an efficient fuel source. Additionally, your body metabolically prefers to preserve lean body mass and, when possible, breaks down fat stores for fuel as much as possible. Only when your fat stores are extremely low or depleted does your body have to then break down protein.

Muscle Breakdown
When glucose and fat stores are depleted, your body will then turn to muscle to break down into individual amino acids for energy. Unlike carbohydrates and fat, your body does not store amino acids, which is why muscle breakdown is the only way to release amino acids for fuel. In typical conditions where you are eating on a regular basis, your body will not use muscle for energy. Typically, protein is used for fuel only in a starvation state. Because you need muscle tissue to survive and move, the natural tendency of metabolism is to spare muscle tissue and break down carbohydrates and fat first.

What Parts of the Body Lose Fat First?
Its complicated, here is the answer:
http://www.livestrong.com/article/333182-what-parts-of-the-body-lose-fat-first/

Grizz

Good post, Grizz!

This is a great topic and you are right that not much is written about this subject, the reason being there are no studies done and there are many variations that affect the results. I have done many fasts in my life. I can tell you that we are all different and different health conditions of the individual has an impact on what the body does to use for fuel.

In my experience, I have always lost fat in my cheeks and around my wrists first. This has happened in every fast in past twelve years. To me this is the most recent fat accumulated in these areas. Then I lose fat around my thighs and buttocks areas. Lastly my belly, which is the oldest fat that is always hard to get rid of.

These are my observations on myself, but we all know that Autolysis is a very selective and subjective process where body discriminates what to use first, get rid of and convert in to usable energy and then excrete the unwanted.

Good luck with your fasting, keep focus on drinking warm water as per thirst, resting and keeping warm. Take it one day at a time, you will do amazing with the fast.

Archus

For males the last bit of fat is stumic and chest for women is butt and legs.

NO such thing as spot reduction. Unless you get liposuction suction. Fun fact you don't remove the fat cell when dieting you just empty the fat cell. Only way to truly loss the fat cell is liposuction.

But for muscle cell when they are gone they are gone your body has to complete rebuild them.

I tend to loose mass everywhere at the same time. My usual BMI is 18.5 -19 and my fat percentage - about 26%. My cheeks run out of fat easier, since I have not much there anyway, but my stomach keeps it longer than legs and buttocks, which account for fast decrease in cloth size.
I feel I loose also a lot of fluids - water bind to minerals and or toxins, which accounts for some of the faster weight loss in the first days of fasting.
Muscles size tends to decrease as well - the fat between the muscle fibers is also burnt, together with the muscle glycogen and the water binding it, as well as some fluids from muscles too.
Overall the size (as opposed to number) of the cells decreases in all tissues, given enough time, with the internal organs spared up until starvation phase, unless breaking the pathological tissue plus healing is under way in them.
This is beneficial, since the internal fluids of the cells get renewed as well - hopefully with good nutrition after the fast.
- starvation takes really long to begin in a normally nourished individual -

I tend to experience similar changes to my body as compared to this guy, although I am not a guy:

https://www.youtube.com/watch?v=0E159Q4Mj0k