The whole idea seems ilogical to me. I am at a more than 1000 calorie deficit....more like 1500. Everyone says have only a 500 deficit for 1lb lost a week and 1000 for 2lbs. I do not think this comes out right....mainly because no matter what you do, not all the excess calories burn fat, whether that is 100cals or 2000cals deficit. To me a 500 cal deficit will result in over 1lb a week, but not all fat. Assume 80% fat, 20% muscle. That means 400cals a day for fat, 100 for muscle. In week you will loose 400x7/9 + 100x7/4 = 311 + 175 = 486grams about 1lb. However, 1/3 of that could be muscle, whether it is 100cal deficit of starvation. Now, if you are weight lifting and assume you are building muscle, what happens in this case? You are still not just burning fat. The logic just seems false and weird.
Then you stuff the amount of fat you take in. If your entire diet is fat, you will preserve some of that and burn alot of muscle. If you have very little fat you will end up burning it all plus more, and a little muscle. I am comfused.

The whole idea seems ilogical to me. I am at a more than 1000 calorie deficit....more like 1500.
1500 deficit??? how long have you been doing that for and has your body gone on strike and pissed off to the pub?

The 500 calorie deficit is a good rule of thumb. If you were only losing fat, it would work out. Since muscle requires a different amount of calories to process, etc, it becomes more complicated. The fact is, debating this is like arguing over what exact shade of blue the sky is. There really is not as much precision with fat loss as people would like. In other words, when the nutrition facts on your food are at best +/- 20% accurate (meaning 100 calories is really 80 or 120) and your energy burned is just a ballpark estimate, etc, a lot of error gets built into it.

So, you are using a starting point. If you are at a 1500 deficit, you are dropping 3 pounds per week. If you are not losing that, you are not in a 1500 deficit. Instead, your metabolism is slower.

Trust me, it works. Sure, some might be from muscle or other things, but if you are consistent (and consistency is the key) then these things average out. I have been doing this and working with others for 3 years now and the fact is when we manipulate calories and use those averages, they work! Without getting lost in the details.

Really, I encourage people to use consistent portion sizes and then instead of worrying about calories, just make portion size adjustments. Even going from 1 cup of oatmeal to 3/4 cup can make a significant impact if you multiple that type of change over multiple meals, weeks, etc.

Jeremy

You are over analyzing...its only a starting point, as Jeremy has said. You need to find out what works for you....everyone is different, and have different levels of caloric need.

1) Eat more. 1500 calories deficit is way too many
2) Jeremy covered the rest. Nothing is exact, it's all approximates so just find what works for you and stick with it. But let it be known, no matter who you are, eating too much or too little will result in negative effects.

I like to deal with portions too for the same reasons Jeremy pointed out. It's not an exact science.

But besides how much you eat (whether measured in calories or portions), you also need to look at what you eat. The types and quantities of carbohydrates, proteins, and fats will affect your weight loss more than just calories in/out. Not all calories are created equal and your body will respond differently to the different types. A 2000 calorie diet of "low-fat, low-protein, high-carbs" is very different from a 2000 calorie diet of "high-fat, high-protein, low-carbs" even though the calorie deficit is the same.

But let it be known, no matter who you are, eating too much or too little will result in negative effects.

By 'negative effects', I assume you mean that you will not achieve 'optimal results'. I agree, but that doesn't mean that someone on a large calorie deficit diet cannot achieve positive results. Each person has different goals, so interpretation of results will vary from person to person.

Take me as an example. I have a deficit of 1500 calories (or more) per day. I have been 'transforming' for a little over 2 months, and I have lost 40 lbs. (about 4 lbs. per week). The breakdown is about 35 lbs. of fat loss and 5 lbs. of lean mass. I'm not happy about losing 5 lbs. of lean mass, but I am ecstatic about losing 35 lbs. of fat. I guess what I am trying to say is that I am more happy about losing the fat than I am upset about losing lean mass.

I am definitely NOT recommending this for everyone. I have done the research, and I know the consequences. But I feel I need the immediate 'results' in order to keep myself motivated.

I applaud those who can maintain a 1 lb per week fat loss over long periods of time. :claplow:

I have a 1500 calorie deficit, and yes I have lost a little over 2lbs a week in the past 2.5 weeks. I am trying to loose weight and fat, not necessarily just fat. I have had a knee problem since I was in high school and was skinny and would like to loose weight to help the problem, which is why i am not too worried about loosing muscle.
A few things: I feel fasting (eating around 1000cals and lots of it protein) a good way to loose weight fast, as long as when you start eating again you dont go back to the same eating habits but slowly adjust so your metabolism has the chance to bounce back up. Most people gain back weight after this cause they just gorge into crappy foods immediately. I have fasted before for semi-religious reasons, and have lost weight and kept it off by slowly increasing my intake and not going from 1000cals to 2500cals overnight.