Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolisms generally remain unchanged.  They will thus burn significantly fewer calories at the new weight than do people whose weight is normally at that level.  Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate.

The conclusion of the argument above depends on which of the following assumptions?
(A) Relatively few very overweight people who have dieted down to a new weight tend to continue to consume substantially fewer calories than do people whose normal weight is at that level.
(B) The metabolisms of people who are usually not overweight are much more able to vary than the metabolisms of people who have been very overweight.
(C) The amount of calories that a person usually burns in a day is determined more by the amount that is consumed that day than by the current weight of the individual.
(D) Researchers have not yet determined whether the metabolic rates of formerly very overweight individuals can be accelerated by means of chemical agents.
(E) Because of the constancy of their metabolic rates, people who are at their usual weight normally have as much difficulty gaining weight as they do losing it.

答案A。请教一下，A不是和题目说的意思相反么？

这道题我选错了，但是现在觉得可能选a与题目最终的结论有关，与lz探讨一下拉~

Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate.

是说这些好不容易减肥成功的人最终又反弹了吧？所以a假设他们不会一直坚持吃低卡

这样想不知道对不对：

假设胖人F和瘦人T一开始每天都吃N卡食物，但是F新陈代谢比较慢，所以会比T积聚更多的脂肪。

现在F结食吃的比T少了许多（N-10000）卡，所以开始变瘦到一定程度。

当F在到达那个程度后又恢复到每天N卡食物（A),由于新陈代谢速度不变，所有又开始积聚脂肪，恢复到原来的体重。（The conclusion)

A答案是将排除另一种解释的可能性。再次谢谢两位的答复！