Do heavy people really burn that many calories at rest?

Hala is on the right path here - be careful with any calculation that uses your overall body weight - the better formulas use your muscle or lean body mass as it is muscle mass that mostly closely determines your BMR (that's why many programs emphasize resistance exercise as a means of preserving as much muscle mass as possible during weight loss.) Loss of muscle mass will decrease BMR while a gain will increase BMR. Changes to fat mass do little, though that will change your overall burn when active as you are moving around more or less overall weight.

Then there's the whole issue of metabolic damage (where we burn less than we are supposed to) that is often present in our obese population - this can be quite variable, and there is not a strong consensus as to the exact causes and solutions. The best quickie check on BMR during our loss phase is to use your ideal or goal weight in those calculators that use body weight as a factor.

When we are obese we actually tend to have more muscle mass than someone sedentary yet skinny. This is because we have to work harder to move around. We also have more cellular mass; more cells means there is a higher demand for ATP, which means the body expends more calories to survive. While lean muscle mass uses more than fat certainly, fat is actually an organ too.

Also, remember though, that calories are all not equal from a hormonal perspective. For instance, when we have high circulating serum insulin, we become primed to store fat. When we are in a state of ketosis, we are primed to burn fat. The entire body becomes fat adapted and it becomes exceptionally difficult to store energy. You still have to watch what you eat given your metabolic rate (I am not entirely 100% convinced we measure it correctly, or know everything about it), however there's like a 300-400 calorie advantage you have if you're in ketosis.

This is because cells use an energy called ATP to function. Glucose is converted to energy equally (basically), however ketosis convers fat to energy at a disadvantage - it takes more energy than it creates. This works to our advantage for weight loss, because it means we need more fat to get the same amount of energy. A bonus is that many tissues in the body prefer ketone bodies/fat for fuel rather than glucose. Even most of the brain prefers fat - it's a myth that most of the brain requires glucose.

You can also be in ketosis due to caloric restriction. Any time you can't eat you actually are in ketosis. For instance, we use ketosis while sleeping, regardless of diet, because we cannot eat while asleep. Babies are also in ketosis when breastfeeding, etc.

At any rate...that tangent train aside, this is an important realization because it means our metabolic rate is partially hormonal. That means we can directly control it in a way other than building lean muscle. This also means it is very unlikely we can permanently damage our metabolism, exceptions involving damages to the endocrine system, such as liver or pancreatic damage.

This is also sort of bad news, and why many of us can't lose weight without surgery: fat stores hormones very well, and this, in part, mucks up a lot of things. However, as we lose weight, our energy needs decrease unless we are doing performance sports, and our metabolic efficiency increases proportionately as a result of the fat loss, hormonal rebalance, and healthier diet.

So when we eat a lot of sugary/carby foods we store fat in other words? Makes a lot of sense. Say, without surgery could someone be similarly effective in losing weight if they simply followed a bariatric diet? Low carbs and 600-800 calories a day, almost all protein?

People do lose weight, oh sure. My friend Tom is a great example, as he lost 290 pounds without surgery, from diet, cycling, and fasting. I went from 750+ to 450ish with diet alone. I've lost 150ish in the past two years since then, and that's with an eating disorder, no thyroid, and three autoimmune diseases. I would perpetually stall even on a low carb diet after I hit 460. I was also constantly starving all the time.

WLS does two things diet and exercise do not. Surgery permanently resets the metabolism. The effect is stronger in the RNY, and most dramatic in the DS. There are RNY and DS patients who are immediately cured of their diabetes. It also eliminates hunger for a significant period of time. While ketosis does suppress hunger, it is nowhere near as good as surgery.

As any dieter knows, it's not losing weight that is hard, it's keeping it off. Surgery still has better statistics. My friend Tom is exceptional as he's kept it off. Not all people are so fortunate, alas.

Most people on ketogenic diets lose even eating 2000 calories a day, if they are strict. The problem is that if you are not strict, you drop out of ketosis. Since we have WLS, our consumption is naturally limited, especially if we eat protein and fat because of what I posted before, and also because protein and fat stimulate the stomach and digestive system to stop being hungry.

Carbs are "fast energy" and we evolved to digest them super quickly. You start metabolizing carbs when you chew, because of an enzyme in your saliva called amylase. Protein and fat, however, rely on the stomach acids to be processed. This is why sleeves work well with protein first - it keeps the pyloric valve shut, and digestion is slowed. Carbs, however, go right through. Since we lack malabsorption, all those calories go straight to the hips.

The other problem is that low calorie diets stimulate hunger. For instance, most people with anorexia eat 800 calories or less a day, and people who fast eat, obviously, little to nothing. Both groups have super sky-rocket high ghrelin levels. The less you eat, the higher your serum ghrelin goes. Due to us having a sleeve, we have far less ghrelin, and are far less hungry because of this.

So, I guess there are benefits and disadvantages to either. Frankly, the only thing I regret about WLS is that I didn't do it 20 years ago and waited this long. Dieting without it worked, but was far more frustrating. Don't get me wrong - it's not necessarily easy. However, it works very well for me.

Thinking about ketosis, meat diets, etc. makes me wonder about how folks are dealing with the carnivore's breath that usually accompanies such diets. Aside from good dental hygiene, what measures do folks take? I remember little gelatin capsules of parsley oil being sold for the purpose of sweetening one's breath from the stomach. I never used these, but I do know that ketosis and/or meat diets can cause very bad breath, and am wondering if this is a particular issue for the WLS population?

As your body gets more fat adapted you waste less of the ketone bodies since it becomes progressively more efficient, so the odor goes away. The odor actually comes from a form of acetone which is created when you break fat (any fat) down.

I've actually never had it, and I eat like 99% meat and dairy.

Anyone with rapid weight loss is using/making ketones, and so it is an issue briefly for many. Usually it doesn't last in my experience.

I searched this site for "bad breath", and found a mention of this product for both had breath and foul-smelling gas: http://devrom.com

I remember my kid complaining that my breath was awful years ago when I was deliberately staying in ketosis. The last thing I want is one more reason to feel embarassed. I'm going to ask my doc if this stuff is ok to take it I find it necessary. Several of the testimonials mention it being used after WLS.

Flatulence typically happens when food ferments or gets undigested. Almost always, carbs are the culprit. Some malabsorption procedures have a bad reputation, but in reality they are not as bad as people say for the most part. It might be good to have handy, but I'd also argue even with the DS, if you have gas issues it will be mostly because of carb intake, and not protein.

At my highest, my minium calorie intake to maintain was 3,100 calories. Adding in activity, I needed almost 5,000 calories to maintain. That made it really easy to lose for a while!

My RMR now is about 1,800, and my overall maintenance intake is 2,500 calories. That's a lot less than before. But there's a lot less of me.

Everyone has given you good points to consider. Remember that we are all different. Many people here maintain on 1000-1200 calories a day even though the calculator says they should be able to consume more than that. I seem to be on the higher end of the spectrum and maintain on 2000 calories a day (right now I am up a few and am cutting back to 1500 calories a day until I lose them).

Keep following your plan. As you get closer to your goal weight, you will need to figure out how many calories you actually need to consume to maintain your loss. This knowledge is power!!