All of the advice I’ve been reading seems to suggest that the recommended daily calorie deficit is 500 kilocalories per day (I’ll just call 'em calories from this point on, though). So if your maintenance (not getting fatter or skinnier) needs are 3000 calories per day, you should consume 2500 calories per day to safely lose weight (or add exercise to offset the difference – more on that below). Since a “pound of fat” is roughly 2000 calories, you should expect to lose 1.75 pounds per week if you don’t cheat on the weekends. That’s also consistent with all of the advice stating 1 to 3 pounds per week. There are many rules of thumb for determining maintenance calories, but they’re so disparate as not to have any credibility in my estimation. It’s something you’d have to measure and figure out for each unique individual. One fact is, though, that pound per pound fat requires less caloric maintenance than other body tissue.
As you lose weight, your daily needs will also decrease, so you’ll have to continue eating less (or excercising more) to maintain the weight-loss velocity. If you’re obscenely obese, you won’t have to worry too much about that for a while, though.
Excerise offers the added benefit of increased muscle mass. Remember you don’t really want to lose weight per se, you want to lose fat. Muscle mass has higher caloric requirements than fat, meaning the more muscle you have – period – the higher your calorie consumption even when you don’t do a thing. Of course not doing anything will cause your muscles to wither and disappear.
I’ve also read that initial, fast weight loss is actually attributable to a combination of water and carbs that are somehow held in suspension in your body, although I don’t understand that mechanism, as well as the loss of muscle, which because of the information above is something that you want to avoid altogether.
If you consume too little, your body will enter starvation mode whereby it becomes more efficient with its calories. This helps form the basis of yo-yo dieting, in that once you’re “off the diet,” your now-efficient body requires fewer calories and the excess food is more readily converted into fat. This is why the 500 calorie deficit is given as a figure for sustainable weight loss. It seems that starvation mode takes a little over a week on reduced calories in order to begin.
All of this in an amalgamated form lends itself to one thing: there’s no such thing as “a diet” but only “diet” (and lifestyle). You must maintain a proper amount of muscle and overall energy use versus caloric intake. In other words, it really, really, really is a simple matter of calories in versus calories out – even if you have some weird “genetic illness,” the laws of the conservation of energy and matter apply universally in our universe.
My experience? Well… my doctor suggested a 1200 to 1500 calorie per day diabetic diet. I cut back to a goal (sometimes surpassed) of 1200 calories per day without changing what I eat (it’s already really varied and healthful), and mostly by giving up beer during the week. It’s amazing how many calories one takes in if you only take a step back and count them. Wow! So by not changing my diet but only changing the calories, I don’t have hunger pangs and have no real motivation for binge-eating. So far it’s been fairly easy.
Now the 1200 to 1500 calorie daily intake is well, well, well below my maintenance needs, but that’s what the doctor ordered. I don’t track anything but calories, since by default every other thing is reduced. I’m not worried about starvation mode because I cheat freely on weekends. My homebrew isn’t going to drink itself! That, plus me and the missus like to go out, and I’m not going to go to a buffalo-wings place to eat a freaking salad. But you know what? I think it keeps the starvation mode at bay, since I’ve yet to gain an ounce on weekends, even after this last, four-day weekend including Easter dinner.
Oh, I’m not meaning to get into too many personal details, but I just wanted to arrive at my current stats: In four weeks and three days, I’m now at 24 pounds off, and the loss has been completely linear (yeah, I’m a chart-making geek). Is it sustainable? I’d like to think it is, but I won’t be disappointed if that rate dimishes, as long as the trend remains downward. In fact, I fully expect it to slow down.
*Read[/] and learn everything you possibly can so that you know what to expect and why to expect it. Then there will never be any cause for confusion or disappointment.
I am certainly no type of medical professional. I’m just trying to share what I think I’ve learned about the entire process during the course of my own lifestyle change.