Initially written by an 'Alim (Shaykh Anas (HA), from Darul Uloom Ashrafiyah), any translation error is mine.
- A tense situation & its remedy
During a period of 1 year 2 months and 14 days [Forty days with one day like a year, one day like a month, one day like a week, and the rest of the days normal], there will be practically no food available under the reign of the false messiah, Ad-Dajjal, unless one believes in this impostor.
In fact before his arrival there will already be nothing left because of severe droughts and then will the one-eyed dajjal emerge with abundance of food and drinks, claiming to be "The saviour".
Asma' bint Yazid  relates the Prophet said 'During the three years just before him (Dajjal), there will be one year when the sky will withhold one third of its rain and the earth one-third of its fruits. In the second year the sky will withhold two-thirds of its rain, and the earth two-thirds of its fruits. In the third year the sky will withhold all of its rain, and the earth all of its fruits, and all the animals will die'. She later confessed, 'O Messenger of Allah, we do not bake our dough until we are hungry' (Musnad Ahmad)
A'isha  says the Messenger of Allah mentioned a trouble (jahd) that happens just before the dajjal. Some sahabahs  then asked 'Which worldly thing will it be better (to have) at this moment?' He replied 'A strong servant who can give drinks to his people [by drawing water from wells]. As for food, there won't be any' (Ahmad 23330, some ahadith may be weak but the global meaning is trustworthy according to Ibn Kathir [Rahimahullah] in nihaya fil fitan wal malahim, pp92-93)
This hadith shows water becoming so rare globally that it would only be found in the depths like wells.
Then will the Dajjal appear, having with him food and water in great abundance. He will come after those 3 years of severe drought and will give to anyone following him.
This will be a worldwide lack of food that's why the temptation of following the dajjal will be great since there will be nothing to eat for those not following him.
The same hadith of Asma' continues : Dajjal will bring a Bedouin and say to him, "What if I bring your camels to life for you? Will you agree that I am your lord?" The Bedouin will say "Yes." So devils will assume the forms of his camels, with the fullest udders and the highest humps. Then he will bring a man whose father and brother have died, and will ask him, "What do you think if I bring your father and brother back to life? Will you agree that I am your lord?" The man will say "Yes," so the devils will assume the forms of his father and brother. Then the Prophet went out for something, and then returned. The people were very concerned about what he had told them. He stood in the doorway and asked, 'What is wrong, Asma'? I said, 'O Messenger of Allah, you have terrified us with what you said about the Dajjal. He said, 'He will certainly appear. If I am still alive, I will contend with him on your behalf; otherwise Allah will take care of every Muslim on my behalf'.
It is important to note that Dajjal won't exert any constraint (ikrah) on people following him ; he will just be proposing it "for free" ie it will be up to one to follow him in the end.
So how will the believers do at this time ? Answer lies in the first hadith : believers will have Dhikrullah as food. The Prophet said, 'The glorification of Allah which suffices the people of Heaven will be sufficient for them'. (eg tasbih, taqdis, takbir, tahlil, tahmid)
- A question & its answer
If a muslim is in a remote place and fears for his life because nothing is available to eat, there is an exception (rukhsa) for him to even eat pork, in fact many 'ulama even consider it wajib for him (azimah, not a mere rukhsa).
Moreover, if a muslim is forced to utter words of kufr to remain alive, then there is ikrah and it is permissible for him to utter such words. Same is the case with acts of kufr under coercion, however in both cases he must reject it in his heart, ie not believe in such words, and also the situation must not be to the extent we come to believe with the heart in the end.
Then why is that during Dajjal's time will it be impermissible to join him, while rejecting him in our heart, just to eat because of such a shortage?
As seen above it is permissible for a muslim who is coerced to utter words/do acts of kufr to remain alive, provided he rejects it in his heart.
However our Prophet Sallallahu 'alayhi wa sallam said in another hadith 'Let him who hears of the Dajjal (Antichrist) go far from him for I swear by Allah that a man will come to him thinking he is a believer and (end up to) follow him because of confused ideas roused in him by him.' (Abu Dawud)
Additionally the Prophet guaranteed us that exceptionally (karamatan) the believers will be kept alive by reciting tasbih, tahmid, takbir & tahlil. This exception is only for this specific time as never in history people remained alive without eating)
This is why in Dajjal's time it will not be permissible to come near him 'only with the body' even with rejecting with the heart. There will be an alternative, we will not die of shortage of food, dhikrullah will suffice us insha'Allah hence the above two examples do not apply.
- Let us prepare spiritually
The pious believers will be saved bi idhnillah. That is why the Prophet Sallallahu 'alayhi wa sallam replied to Al-Mughira bin Shu'ba [RadhiyAllahu 'anhu] who was quite worried saying 'I asked regarding Ad-dajjal. The Prophet said to me, "What worries you about him?" I said, "Because the people say that he will have a mountain of bread and a river of water with him (i.e. he will have abundance of food and water)" The Prophet said, "Nay, he is too mean to be allowed such a thing by Allah" or "he would be more insignificant in the sight of Allah than all these things (belonging to him)"' (Sahih Bukhari & Muslim) which means 'he is too despicable to Allah, Allah won't make the sincere, complete and pious believers (muqineen) distracted by him'. (Fath-ul-bari)
But what would unprepared muslims choose between being satisfied with spiritual food (subhanallah, alhamdulillah, Allahu akbar, la ilaha illallah...) versus mouth-watering physical food dajjal will offer whilst they are hungry?
It will be a double test : a) resisting at the physical level and b) remaining convinced & certain of the truthfulness of Prophet Muhammad ['alayhis salam]'s words. Both are linked : the gnawing hunger may lead to doubt (shakk) Prophet ['alayhis salam]'s words; some weak believers may say 'The one-eyed messiah is a good and charitable man, he's giving food while there is a famine; and by the way are we really sure of the hadiths attributed to the Prophet ? It's debatable, the Prophet ['alayhis salam] wouldn't order us not to eat, the mullahs say nonsense, they don't get the situation at all!'.
We should not prepare spiritually just because of dajjal's venue, rather this must be made in all circumstances. That is why the Prophet ['alayhis salam] said 'When three things appear faith will not benefit a soul who has not previously believed or has derived no good from his faith: the rising of the sun in its place of setting, the Dajjal, and the Beast of the earth'. (Sahih Muslim). The doors of repentance (tawbah) will be closed only after the sun has risen from the west, the dajjal will come before but his arrival is mentioned here, not because tawbah won't be accepted (repentance will still be possible under Prophet 'Isha [Jesus] alayhis salam), but because this trial will be so intense that just like a non-muslim won't believe in the Message of Prophet Muhammad ['alayhis salam], the same way a muslim who had remained in complete heedless won't be able to do good and reform himself; the trial will expose everybody's internal condition.
May Allah give us tawfiq to remain steadfast on His deen, and to follow every commands of His Rasul just like we believe in His Prophecies.