Before Eating
Before eating a Muslim should: 1. Wash their hands; 2. Say Bismi(A)llahi (A)r-Rahmani A(R)-Raheem, which means: "In the name of Allah, the Beneficent, the Merciful." By doing so we are reminded that it is through the Mercy of Allah (s.w.t) that we are blessed with food to eat.
While Eating
While eating, a Muslim should:1. Use their right hand
2. Take food from the side of the dish nearest to them, and not pick at it, looking for the better pieces.
3. Take a moderate amount of food on their plate, allowing others to have their fair share.
4. Not waste. If you are unsure of how much food you need you can start off with a small amount and then if you're still hungry you can go for a second round.
5. Eat with other people if possible.
6. Avoid gluttony and overeating.
Rasulullah (saws) is reported to have said that when eating, one third of the stomach is for food, one third for drink, and one third for air (it should be empty). If this advice is followed a Muslim will derive many benefits from it for their health. The bad habit of burping will also be curbed. If you have to burp in public while in front of others you should turn your face to the side and cover your mouth with your right hand. After burping, one should say Alhamdulillah (All praises are for Allah s.w.t).
After Eating
After finishing the meal, a Muslim must thank Allah (s.w.t) and say: Alhamdulillahi (A)lladhi at'amana wa saqana wa (a)j'alna min (a)l-Muslimin (All praises are due to Allah who gave us to eat and to drink and made us Muslims. )After this Muslims are recommended to:
1. Wash their hands
2. Rinse their mouth
3. Preferably, clean their teeth with a Miswak or toothbrush.
In Christianity people are advised to thank God for the food before the meal. However, In Islam we are advised to thank Allah after the meal. This is very significant because Allah (s.w.t) knows His creation best. Perhaps before the meal if the individual is extremely hungry they may rush through and very quickly give thanks without it really coming from the depths of their heart. However, after the meal the individuals stomach is satisfied and they can give a more sincere and thoughtful thanks without having the urge to rush it in order to fulfill their desire. Also, in Islam if a person's mealtime and their prayer time come at the same time and the individual is very hungry than it is preferred that they eat first and then go due their salah (prayer). Subanhallah these simple things really show the infinite Mercy of Allah (s.w.t) and the beauty of Islam.
Source: Islamic Tahdhib and Ahlaq by Aisha Lemu