She lost a lot of weight due to illness; is it permissible for her not to fast?
Question

                Last year I suffered from some health problems which caused me to lose a lot of weight, and I was not able to fast throughout the month of Ramadan, on medical advice. This year, I have recovered from those problems, but I am still below my ideal weight. My parents and close friends have advised me not to fast, but I disputed with them and argued, because I feel that I am well enough to fast. My mother called the imam of the local mosque, and asked him about my case, and he said that I should not fast so long as I am below my ideal weight. Should I listen to their advice and make up the fasts when I am fully recovered, or should I fast whatever the case?
Praise be to Allah.
	We ask Allah, 
	may He be exalted, to grant you a full recovery and well-being.

	You should seek 
	the advice of the specialist doctor who supervised your treatment.

	If he confirms 
	it you are able to fast, and that it will not have any impact on your health 
	and full recovery, then this will put your and your parents’ minds at rest, 
	by Allah’s leave, and then you will be able to fast, after seeking the help 
	of Allah.

	But if the 
	doctor thinks that fasting will be too difficult for you, and that it may 
	cause you some health problems, then it is better for you not to fast, and 
	then make up the fasts after Ramadan, when you are fully recovered, by 
	Allah’s leave.

	Ad-Dardeer al-Maaliki 
	(may Allah have mercy on him) said:

	It is 
	permissible not to fast in the event of sickness which it is thought – on 
	the basis of the view of a knowledgeable doctor – will be exacerbated by 
	fasting or recovery will be delayed thereby. The same applies if the sick 
	person will suffer hardship and exhaustion if he fasts.

	End quote from
	
	ash-Sharh al-Kabeer ma‘a Haashiyat ad-Dasooqi 
	(1/545)

	Shaykh Ibn 
	‘Uthaymeen (may Allah have mercy on him) said:

	What makes it 
	permissible to break the fast is that which the sick person fears may 
	exacerbate the sickness or delay his recovery. This is what makes it 
	permissible to break the fast. So if he fears that it may exacerbate the 
	sickness or delay his recovery, or cause undue hardship, in the sense that 
	the sick person will become exhausted if he fasts, all of this makes it 
	permissible for him not to fast.

	As for that 
	which is not affected by fasting, such as toothache, pain in the finger and 
	so on, then this does not make it permissible to break the fast, so long as 
	there are no consequences that will result from that. As for simply having a 
	toothache, it will not help a person if he breaks the fast. But if the 
	doctor tells him: If you break the fast and eat something, this will relieve 
	the pain of the toothache, then in that case we say: There is nothing wrong 
	with it, because sometimes lack of food may prolong sickness and pain; and 
	the same may be said concerning eye pain, for example. If fasting will 
	affect it, then he may break the fast, but if it will not affect it, then he 
	should not break the fast.

	End quote from
	Ta‘leeqaat ‘ala al-Kaafi by Ibn Qudaamah (3/123).

	The mere fact 
	that a person is below his ideal weight is not a reason for not fasting; 
	rather he should look at what may result from fasting of hardship, 
	exhaustion or harm, and whether he can make up for lack of nutrients due to 
	fasting by eating at night or not. It is essential to consult a trustworthy 
	doctor and find out what advice he can give you.

	For more 
	information, please see fatwa no. 140246.

	And Allah knows 
	best.