I'm watching Ruby and never realized how thin her hair was. I wondered why she constantly wears some sort of head covering every time she goes out. Now I know. She said she lost quite a bit of hair because she used to yo-yo diet.

I haven't lost any hair nor has it gotten thinner. However, I wasn't over 700 lbs and lost over 350 lb either.

The hair extensions she did turned out awesome!

No, fortunately I have not.

My hair actually got thicker, shinier, and healthier throughout the weight loss process because even though I was eating enough calories to keep me obese at my highest weight, my food was completely lacking in nutrition. I now eat extremely nutritious foods and my hair(and nails and skin) really show for it.

YES but its not the weight loss, its was nutrional issue, for me the dr said my zinc levels were very low, thus the hair loss!
I would suggest a blood test to check.

Yes. It got thin and brittle and started falling out.

But that was the last time I lost weight -- when I dropped from 135 to 115 in under 3 months with a period of veganism and a lot of self-deprivation. I was battling depression and simply skipped tons of meals. This time, I've tracked my food, exercised, eaten as much as before (though of different things), and my hair has gotten better. I'm not losing quite as quickly, but I look tons better. My experience is evidence that crash dieting is a horrible idea.

Nope! Not during weight loss.

It got very thin when I was working a seriously stressful job, though. It's just now starting to grow back.