It's the day of your shoot. You've been starving yourself for weeks. Just six more hours and we'll be shooting and when you're done you can go and have a big meal.
Except is doesn't work that way...
It might surprise you to know that over the years I've had no less than 8 subjects feint during photo shoots. One let out a massive fart on the way down. No one got seriously injured, but the reason was simple. Every one of these women had extremely low energy levels due to starvation.
If you want to go on a crash diet for the month before the shoot be my guest, though I'd prefer you just concentrate on healthy activities and diet. But on the day of the shoot you're going to get a long workout. Eat a sensible breakfast. Drink plenty of water. If the shoot is later in the day, eat a light, but filling lunch. I promise, the food in your tummy won't show, but the extra energy you feel will make you feel much better.