Can You Eat Before Ghusl After Intercourse?

It is not obligatory to do ghusl from janabah when one wants to eat, rather it is Sunnah to do wudu when one wants to eat. This is a matter on which there is consensus among the scholars. 

The evidence for that is the hadith of `Aishah (may Allah be pleased with her), that the Prophet (peace and blessings of Allah be upon him), when he wanted to eat or sleep at the time when he was junub (in a state of impurity following intercourse ), he would do wudu. (Narrated by Muslim, al-Hayd, 461)

Shaykh Ibn ‘Uthaymin said in al-Sharh al-Mumti’: “It seems to me that the one who is junub should not sleep without doing wudu , this is mustahabb, as is also the case with regard to eating and drinking. Some of the scholars said: it is not makruh for him to eat or drink without doing wudu when he is junub.” (Al-Sharh Al-Mumti’, 1/310-311)

For more, please see these answers: 20847 and 14225

And Allah knows best.