I have a job with sufficent salary to take care of me and I live away from my family. But every weekend I pay a visit to my family. Anyway my father deals with interests, he has taken a loan thus pays interest. When I go home on the weekend I have to eat from my home, of course. What should I do?. I know food from interest is haram but if I don't eat from home on weekends it will be a big problem. They expect me to come home every weekend as well. What should I do ?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

One is required to search for Halal food and to avoid what is doubtful and Haram.
It is recorded in Sahih Muslim from Abu Hurairah that Allah's Messenger (SAW) said: "Allah is good and accepts only that which is good." He has ordered the believers to do that which He has ordered His Messengers to do. As such Allah, the exalted, has said: {O (you) Messengers! Eat of the Taiyibât [all kinds of Halâl (legal) foods which Allâh has made legal (meat of slaughtered eatable animals, milk products, fats, vegetables, fruits, etc.], and do righteous deeds…….} [23: 51] {O you who believe (in the Oneness of Allâh - Islâmic Monotheism)! Eat of the lawful things that We have provided you[] …….} [2:172].
Then, The Messenger mentioned (the case of) a man who has traveled a long distance unkempt and dusty - and who raises his hands towards the heavens and pray: 'O Lord! While his food is Haram, his drink is Haram, his clothing is Haram and he is fed with Haram; then how could his prayers be answered?" [ Muslim ].
So, whoever has Haram wealth, it is Haram to take or use such wealth. Furthermore, if one knows that so and so food is purchased with Haram, it is also Haram to eat from it even if its owner is your father. For sure, eating what is Haram results in bad consequences and rejecting one's supplications is one of those bad consequences as stated above.
In addition, eating what is Haram spoils one's heart as reported by al-Bukhari and Muslim from al-Nu'man Ibn Bashir That the Prophet (Sallallahu Alaihi wa Sallam) said: "The Halal is clear and the Haram is clear, and in between them there are some things that are doubtful…. Truly! There is a lump of flesh in the human body; when it is healthy, the whole body is healthy" . This Hadith clearly indicates the relation between spoiling of one's heart and eating what is Haram, and vice versa. The above ruling is applied when all of your father's wealth is Haram.
But, if your father's wealth is mixture of Halal and Haram, then it is Halal to eat (and take) from him.
Also, we draw your attention to the fact that it is necessary to give advice to your father and to order what is good and forbid what is bad, but in wisdom.
Allah knows best.