I'm really worried about mt best mate. He seems to be obsessed with losing weight and getting down to 8% or less body fat. In the last week he lost 8lbs and has lost about 1.5st in the last few weeks. he only eats about 500 cals a day and then spends 2-3 hours in the gym every night. How is this going to affect his body???

this is not good, you are right to be concerned, his muscles will break down and he'll ruin his body's calcium and bone density, also it is putting a great deal of pressure on his heart.500 cals a day is too little, he should be on at least 2000, he won't be able to stick this for long, perhaps you could have a word with the gym as they wont be happy with him training so much when he's eaten so little.

as soon as he stops this diet he will put the wieght back on .... its not a good idea i was advised by my gp to aim for a loss of just 3lb per week as a slower loss means its more likely to stay off as your body adjusts itself to your new routine.. also i was told never to have less than 1000 calories each day definatley never below 500 your friend is sort of anorexic with what he is doing.i do know of a website which if you are interested in passing onto your friend i can let you have it works out how many calories you can consume each day just to maintain your wieght with out the excercise it will also help him to see how many calories he is burning with simple things like housework or whatever .. i would definatley talk to him about it he may not realise there is anything wrong witht the way he is doing it maybe say i want to help and be supportive but if after youve done all this work you do put it back on i dont want you to be crushed so maybe we could look at a better way which will be more benificial... good luck

You are right to be worried what your friend is doing. It is not safe or healthy for his body. I know from experience. I was only eating ice chips. I was getting 0 cals. I was getting so weak that i was passing out. I knew what i was doing was wrong but i had to
make the change. Have you friend check out this website. I bought this book and it got my life on track. I was able to eat normal and lose weight. It worked wonders.
www.dietsolutionstoday.com
Good luck