It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Prophet of Allah (peace and blessings be upon him) said: "The best of my Ummah is the generation among whom I was sent, then those who come after them, then those who come after them. Then peoples will arise who will give testimony though their testimony is not sought, who will swear oaths though they are not asked to swear, who will betray though they are not entrusted with anything, and obesity will become widespread among them."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15671