The believer should be keen to make the best use of his time and not to waste it. Many women, as mentioned in the question, spend hours and hours in preparing various kinds of food. 

The believer should reduce his food intake and his main concern should not be to enjoy whatever he desires of food and other things, even if it is permissible. 'Umar ibn al-Khattaab entered upon his son 'Abd-Allaah and found him eating meat, and said, "What is this meat?" He said: "I fancied it." 'Umar said: "Every time you fancy something, you eat it?! It is enough extravagance for a man that he eats whatever he fancies!" May Allaah be pleased with them. The Muslim should limit himself to what he needs of food, and not go beyond that. 

Moreover, the time that a Muslim woman spends in preparing food could be used in remembering Allaah or reciting Quraan whilst she works. it should also be noted that if her intention when preparing food is sound, namely to serve her husband and children, then that is an act of worship for which she will be rewarded. 

Shaykh Abd al-Azeez Aal al-Shaykh said: 

Her work in her house is an act of worship to Allaah, and her doing her household duties and taking care of her children are an act of worship to Allaah, so she is in a state of worship, in sha Allaah. So she should make the most of the time in order to remember Allaah; it is permissible to remember Allaah whilst preparing food, praise be to Allaah. 

Majallat al-Buhooth, 58/81.