[Evgeny]

Studies have shown that overweight people don't necessarily eat more calories or have less active lifestyles than their normal weight peers [1][2][3][4].

These appear to be observational studies based on self reporting. There are multiple studies that showed overweight people underreporting their caloric intake by up to 50%. Interestingly, people with normal and less than normal weight ofter overestimate their caloric intake, such as [1].

There are enough clinically controlled studies done that prove that caloric intake is the primary determinant of weight.

[1] http://www.ncbi.nlm.nih.gov/pubmed/1454084

[kenesom1]

The accuracy of self-reported energy intake using the 24-hour daily recall method has been shown to be consistent across BMI levels:

"Accuracy of recall was not related to body mass index in that the obese men recalled food intake as accurately as the nonobese men." [1]

Accelerometers were used in the Chinese study to measure physical activity:

"No differences in PA [physical activity] and SB [sedentary behavior] were found across different BMI categories." [2]

A European study where the childrens' parents were doing the reporting rather than the subjects themselves concluded:

"The data suggest the belief that overweight children eat more than non-overweight children is not correct." [3]

Studies on identical twins showed that caloric intake didn't account for differences in weight between twins. Specific types of gut bacteria present in low-weight individuals were found to have a protective effect against obesity however. [4][5]

There is little difference between the energy intake of most overweight people and their normal weight counterparts. Factors like gut biology and intestinal absorption play a much more important role.

The Nutrition Science Initiative was developed to address the need for more clinical research in this area. [6]

[1] http://www.ncbi.nlm.nih.gov/pubmed/15054345

[2] http://www.ncbi.nlm.nih.gov/pubmed/11753586

[3] http://www.ncbi.nlm.nih.gov/pubmed/24527563

[4] http://www.amazon.com/The-Diet-Myth-Science-Behind/dp/029760...

[5] http://www.sciencedaily.com/releases/2014/11/141106132204.ht...

[6] http://www.wired.com/2014/08/what-makes-us-fat/

[Evgeny]

The accuracy of self-reported energy intake using the 24-hour daily recall method has been shown to be consistent across BMI levels:

CONCLUSIONS: Under controlled conditions, the USDA five-step multiple-pass method can

Yes. We need controlled conditions.

"No differences in PA [physical activity] and SB [sedentary behavior] were found across different BMI categories." [2]

The parents of children recorded dietary intake for a week using the food weighing method.

No. Please let the scientists weigh the food under controlled conditions.

A European study where the childrens' parents were doing the reporting rather than the subjects themselves concluded:

No. Please let the scientists weigh the food under controlled conditions.

Studies on identical twins showed that caloric intake didn't account for differences in weight between twins.

The ScienceDaily link does not give much relevant information. So they found sets of twins whose weight differs, and the gut bacteria composition differs. Interesting. What did they do next to disprove that caloric input determines body weight? Did they assign twins to certain diets to see how body weight changes? No, and the word "calorie" is not even mentioned at all.

In fact, all I get from the article is correlation - lack or presence of certain types of bacteria is correlated with body weight. Here's an easy possible confounder: what if lack or presence of bacteria increases or lowers the appetite, causing caloric intake to change and thus leading to weight gain or loss?

The Nutrition Science Initiative was developed to address the need for more clinical research in this area. [6]

Yes. As long as all food is measured by the scientists and there is no possibility the participants are getting extra food elswere, or not eating what they are supposed to eat, I'm very eager to see the results.