How can the national weight control registry claim dieting doesn't slow metabolism?

This article claims that ex-obese individuals have metabolisms working at the same speed as people who haven’t lost weight.
URL=]This article said that

“compared to the general population, are consuming less energy and a lower percentage of energy from fat. Among this sample of successful weight loss maintainers, maintenance of weight loss is associated with continued consumption of a healthy low-energy, low-fat diet”

Also, i remember reading that the average weight is 160-170 of a registry member (im trying to dig up stats but cannot find any. if/when i do i will post them) however many websites like this one say that the average NWCR individual eats 1400 calories a day and burns 400 in exercise. If this is true that works out to a 6.25 calorie/lb ratio. This is extremely low almost 1/2 what normal people have as most metabolic calculators require multiplying weight by 12-15, and most ‘standard’ dietary guidelines say roughly 2100 calories for women and 2900 for men so unless men become 464 lbs on average sometime soon then 6.25 calories per lb is very low.

Has anyone here lost weight and kept it off? how many calories a day do you eat? i know recording your food intake is important so i assume alot of you who have can provide me with this info.

Also, if it is possible for metabolic rate to be cut by 50% then why doesn’t the body do that 24/7?