due to和because的差别?

lao2lao2

小弟在做题目(Sentence Correction)时看到这样的解释
\"A\" and \"B\" use \"due to\" unidiomatically to mean \"because\";
properly used, \"due to\" is synonymous with \"attributable to\".

在我的理解中because常被翻译成“因为”，due to翻译成“由于”，
attributable (attribute) to翻译成“归因于”
但中文这三个解释彼此间的界线满模糊的，因此想请教各位高手不吝给予较清楚的解释，
谢谢！
（以下是原题的正确句子）
Two new studies indicate that many people become obese more because their
bodies burn calories too slowly than because they eat too much.