I don't mean in terms of total weight loss journey or anything, I'm talking about the simplified "calories in-calories out" scientific method of weight gain and loss. If you were to eliminate any other factors such as slowing metabolism, and disregarding week 1 where there is large water loss, how long does the chemical process take for you to convert a 3500cal defecit into an actual lb of body fat lost? What is the process? For example, do you lose water and glycogen weight first in order to feed the body and then your system sends out the messages to go and get some stored body fat and change that stored body fat into usable glucose for energy, how long does it take to change body fat into its component parts, and what are they?

And is it exactly the same process in reverse, or does the body have a different system for turning excess food into stored fat?

It's just that I see things like "last chance workout" and that makes me laugh because I think if you are going to work out and then go and get weighed in the next half hour then the only extra weight you are going to take off is sweat. Or people who say they ate something last night and now they are really fat and I think don't be daft it's just bloating, or even those who eat then weigh themselves and say they put on 1lb - well yeah, if you eat 1lb of food then you will weigh an extra 1lb till you do a 1lb BM!

How long does the process actually take to go and get body fat and break it down?

My trainer explained it this way. When we eat we consume some fat that is stored right away for future use and glycogen which is sugar is converted into fat if it is not used. So when exercising and dieting the first to be use is glycogen, easy fuel to use but if you consume simple carb in great quantities you have lots of fuel and fat won t be used and your risk having the glycogen converted into fat. That is why you need to have a diet that is low in simple carb.

Water in your body is used to transport fat, glycogen and protein to your organs and muscle, without this water the transfer is difficult and toxins build up.

She suggest doing a warm up, then weight lifting to finish with cardio. If you weight yourself after a weight lifting session you will have a weight increase, minimal but your muscle retain water for a little while in order to

Sorry push on the wrong button, your muscle retaining water in order to recuperate for a few hours.

She also states that our body. Does not let go of fat easily, it will comme off but slowly, it is very difficult for our body to metabolise the fat. She sticks to one or two pound a week anything more than that is water or worse you are loosing muscle mass.

No one can give you a short answer to this. The body's metabolism is an extremely complex process, and not only that, it changes. Although people like to use the "machine" analogy, the body isn't really a machine. Its actions aren't totally predictable based on generalities, averages, and modeling--and that's especially true for an individual.

If you'd like to sign up for some human physiology courses at your local university, you can find out more.

Jay

That's a really good question. I always smile at the notion that what I just ate or burned off instantly appears or disappears on the body. It's like a little factory in there and it takes time for all the gears and conveyor belts to process what you're putting in and out. As for how long of a process, I have no idea! It does explain the "whoosh" phenomenon, though.

All I know is that I always weigh less after a day I have to pee a lot. It's true!

I don't have anything scientific, but I know when I've had 2-3 lower calorie, higher exercise days in a row, it takes 4-ish days for me to see the results on the scales. That's pretty consistent for me.

Great answer !!

Eliana, I bet that's because you're drinking more and staying hydrated and thus not retaining water.

Ditto what JayEll said - one of the maddening frustrations of the process is that nutrient levels cause different things to happen in different people. There's a growing field called "nutrigenomics" that's exploring how genes get switched on and off by nutrients (including those responsible for fat-burning, energy creation, muscle building, disease initiation). It's absolutely fascinating - that the genes you were born with can be flipped on and off just by how you eat - and especially WHAT you eat. The "3500 cals = 1#" rule probably won't even exist in another 10 years.

Nope. You'd think so, but nope. I know the scale will drop the next day if I have to urinate more on a day I am not taking in a lot of water. I don't focus on water so much anymore like I used to. It doesn't seem to have an effect one way or the other so I just always have a water bottle handy, but I don't force it.

This is generally a "whoosh" effect, releasing water weight.

A ballpark? I mean, could it be as fast as an hour in some people and as slow as a week in others, or is it between 24-48 hours, 2-3 days... there's gotta be a range and distribution if it's been studied at all. Same as I can't tell you how long a particular individual will take to run a marathon, but I can tell you the fastest any human has ever done it, the longest it's ever taken anyone and the time range where the vast majority of runners finish.

Love to, but it's the only course you cannot just sign up for if you want to, you must be sponsored by a employer in the field of health and health sciences. How you get a career in such a field without a qualification in health sciences I don't really know, but there you go.

I don't know that there is a ballpark estimate that would work universally. Like AZ_Sunrises, I notice a loss a few days afterward, but for me the lag is only two or three days. For others, it might be five or six, maybe even a week.

If you're looking for that as a ballpark estimate, then I guess two days to a week is a fair one. There'll always be outliers, of course.

It is a fascinating thing to contemplate, I agree. Pretty interesting to think about how the body processes and stores this morning's breakfast.

Mine varied as I went, too. At first, it seemed that my work showed up within 2-3 days. Toward the end of my journey, I would be on plan for an entire month and lose whatever I was going to lose that month in the 1 week after my period, which means my lag between action and scale was up to a month long.

I don't think there is any way to study this because it's the net of so many different processes. Here are just some scenarios to consider:

You sleep for 8 hours. During that time you don't eat. Your body has to burn calories to keep you alive while sleeping. If blood glucose drops too far, the hypothalamus (part of the brain) releases hormones that ultimately cause the liver to release glycogen to bring up the blood sugar. Basically, you are fasting all night. (That's why the first meal is called break-fast. ) This is one reason that people often weigh the lowest first thing in the morning, although the fact that they haven't drunk water also means they are dehydrated.

You are walking briskly on a treadmill. For the first 10 minutes or so, your muscles are coverting stored glycogen into energy. Once the glycogen is gone, the muscles must use something else to produce energy, and so they start to convert fatty acids instead. They also use glucose from the blood. However, the brain has priority over everything else as far as glucose goes. Exercise too long and too hard, and you'll pass out. The point is, however, that muscles are now using fat along with other molecules to produce energy.

If during the day you are eating fewer calories than you are burning overall, then the body uses whatever molecules it can find to produce glucose. It is sometimes as easy to break down protein as it is to break down fat for this purpose. That's why one can lose muscle (and other lean body mass) as well as fat when dieting. Exercise, especially weight training, can help prevent this, but not entirely.

But if you're looking for something like, "OK, I ate 3500 calories of sugar, when does that become a pound of fat?" there is just no answer for that. It depends on too many variables.

Also, don't forget that some of the oxygen we breath and the water we drink also goes into making molecules in the body.

All I can tell you is that if you consistently eat just 100 calories more than you burn every day, you can easily gain 10 pounds a year. That's not a lot! It's just a tablespoon of butter, or a couple of Oreos.

Jay