Here’s a good article that explains it:
http://anthro.palomar.edu/adapt/adapt_2.htm

I think this is wayyyyyy to complicated analysis.

A person need not have a Phd. in biology or be scholarly to lose weight.

Just follow a healthy lifestyle and don’t go all crazy with trying to lose it all at once. Simply cut a few bad things out of your diet and replace them with some sensible activity like walking the dog, cooh hunting, or swimming in the river. Or, if you have some steep slopes around your place, then, walk up those. Another good activity that burns lots of calories is spliting and stacking wood or cleaning out the hogs’ house (a.k.a., scoop’in poop) Replace the drive thru at Burger King with any of these activities and the net deficit for that day will be more than several hundred calories.

I started my fat loss journey as an obese male, 38 years old, weighing in at 225 lbs at 5′ 5″ height. I lost 70 lbs over a period of 7 months, got down to 10% BF and saw my abs for the first time in my life, by establishing a daily caloric intake that would create a deficit, then tracking everything I ate, and working out 3 times a week for 30 min each time, doing a combination of high-intensity resistance training and cardio.

I did not do “low fat”, “low carb”, “high protein”, etc. I simply made sure I ate sufficiently less to create that caloric deficit. I did not miss out on any of my favorite foods (even what others call “junk” foods). I just simply made them part of my daily budget. Some days I was over my target, and some days I was below my target. But I made sure that at the end of the week, I averaged my target number.

For me, prolonged caloric deficit is the answer to fat loss. Period. Full stop. End of story. It is NOT macronutrient exclusion or over-prioritization, nor number of meals per day, nor elimination of processed carbs (I still ate pizza, regular bread, tortillas and the like regularly, although not exclusively). I think that it was this “flexibility” that I had built into my diet plan was what allowed me to stick 100% to my “diet” over the 7 months… simply because I kept an eye on the most important metric of all… caloric deficit.

I *cringe* when I hear people talk about having to eat celery sticks and yogurt, go on medically supervised VLCDs, etc. because I know the *hell* that accompanies those failed approaches…. and find it totally unnecessary. My journey was painless and struggle-free once I took starvation, deprivation and dogma out of the equation.

With the first 2, I lost 100 pounds EACH!
I gained all back and more.
Why?

Simple.
I NEVER got to the heart of WHY I was doing was I was doing to myself by eating the way I was!!

I am an emotional eater, plain and simple. My mom died, I ate. My dad was abusive, I ate. Had a bad day, I ate and on and on. I am NOT blaming a single person or incident for what I have done to myself. However, I have never, ever, once had a physician sit me down and suggest I have a full physical and blood lab done to see first, if there were any medical factors causing my weight gain. Nor did any of these physicians ever suggest that I ALSO get some psychological intervention to get to the ROOT of WHY I was eating myself to death!!

The fast food and weight loss industries go hand in hand, believe me. Drive through Burger King and then drive right into Jenny Craig! Do you know who was assigned to be my “consultant” or diet manager, if you will? A 19-year old college student (who was a sweetheart) working a summer job! She had NO professional training in how to handle my issues! She was “trained” in pushing the newest food addition or a vitamin that was on “sale”. This is “Drive-Thru” weight Loss. After I left the program, I gained it all back and more because I NEVER treated what was really wrong in the first place and that was WHY I was overeating.
Once I did that, (2 years of food therapy), the weight FELL off! That and a full physical and blood lab. Turns out I have MAJOR thyroid issues and hormonal imbalances that are now treated and not blocking my full potential to get the weight off. I also called my local hospital and inquired about any weight loss programs they might have or know of. These are NOT lose-weight-quick, programs. So if you’re looking for that, this is not the way to go. These are supervised by an MD and require you to have a full physical with all that goes with that (blood work, stress test, etc.) and then you and your physician determine which program ( some include Gastric Bypass or the Band) is best for you; mine was a very low-calorie diet in the form of shakes for a 8 weeks and then meeting with a certified nutritionist who teaches you how to eat REAL food in a real manner. You are weighed in each week and also go to behavior modification classes run by MD’s and psychologists specializing in food addiction. Most insurances will cover 80%.
It was HARD work and very stressful at times, but NOT as stressful as wondering daily if I was going to die from heart disease or in other obesity-related ways.
This isn’t rocket science people. There is NO one, who can do this for you. NO pill; NO diet guru; NO magic formula. You can do study after study and have symposiums on obesity and the newest way to get the weight off. But NOTHING wil work until YOU take care of YOU and get the help you deserve.
Just take the reigns and care enough about yourself to find a physician who will out you FIRST and get you started on the path to health!!

If you truly feel that your client’s reported caloric intake is truthful and accurate, then i would highly encourage that person to get a cmp to see if any overt hormonal issues are at play there. That being said, with the aforementioned “woosh” effect kept in mind, I have yet to find a client who couldn’t lose weight or girth over several months. The use of the Bodybugg seems to work really well and I’ve found that working towards a “calorie burned” goal is significantly more effective than “activity time” goals (i.e. 45 minutes of cardio).
but like Lyle said, take a client with a modest caloric reduction and H2O weight can seriously obscure the fat loss as assessed by scale weight. But have that client make a modest caloric reduction (say 250 calories) with 300 calories a day extra burned through exercise and now we’re getting a a very attainable loss that will manifest over a couple of months even with a significant amount of H2O retention. The problem is one “cheat” meal can put a huge dent in the equation for people with a very low BMR. My BodyBugg says that I can burn 4500 calories a day with very moderate cardio and weights so i have the luxury of being able to fudge a little here and there. I really feel bad for the girls who have to count every single calorie.
anyway the point is, I’ve seen plenty of food logs from people who will swear on their mother’s grave that every piece of celery has been logged rather than suffer the embarrassment and humiliation of conceding a late night cheeseburger or a few extra bowls of cereal.

Not all people fit into the cookie-cutter on insurance company designed scales. Studies prove that thin people have the same co-morbidity issues that obese people have. One can be obese and have full mobility with plenty of energy.