All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is known that what is predominant in fashion and diet and fitness magazines is that they contain many disadvantages, as they publish seductive pictures which cause the spread of Zina (fornication or adultery), and they invite the Muslims to westernize themselves. Also, they propagate the dress of non-Muslim and dissolute people. One should not only boycott such magazines, but rather should advise other people not to buy them so that no one would buy them. Buying them is contributing to the continuity of their publication and helping the owners of these magazines in their falsehood.
However, if we presume that you find such magazines at hand [without buying them] and wanted to read them, then it is permissible to do so, and in principle, you are permitted to look at pictures as long as they do not expose the 'Awrah (parts of the body that must be covered in Islam) which a woman is forbidden to look at, and provided you do not fear to be affected by the implications of such pictures, like resulting in you not remaining religious. For more benefit, please refer to Fataawa 88842 and 84062.
It might be difficult for a person to avoid being influenced, as he may become influenced without realizing it. You must remember that the devil whispers to the person and one’s own desires order him to do evil. Therefore, we advise you to stay away from these magazines and read the Quran instead and use your time in what benefits you in your religion and in your worldly matters, like reading the Quran, books about the biographies or righteous men and women, and other beneficial books.
Finally, it should be noted that a Muslim woman should not be too interested and impressed by fashion dresses and the slimming of the body, as this might lead to the weakening of one's faith and hardens one’s heart.