We stayed with friends over memorial day weekend and the mom of the family absolutely avoids any kind of fat. We had 4 meals:
Lunch: Turkey sandwiches with fat-free mayo, Pirate's Booty (nearly fat-free corn puffs), fat-free chips, fat-free milk, grapes, lemonade with sugar.
Dinner: Frozen pizza (didn't see the box but from the taste both the crust and cheese must have been non-fat), salad with vinegar dressing with a splash of oil ("to make the dressing healthier I substitute most of the oil with vinegar" she said), sliced tomatoes, grapes, carrot sticks, non-fat ranch dressing. Berries with fat-free pound cake and low-fat ice cream for dessert.
Breakfast: bagels with fat-free cream cheese, fat-free butter substitute, a fat-free strudel type pastry, fat-free milk, lemonade with sugar.
Lunch: Same turkey sandwiches.
Dinner: Hamburgers (didn't see the package but they tasted like the "95% lean" beef), corn with fat-free butter substitute, fat-free hot dogs, fat-free cheese, fat-free mayo, ketchup, relish, pickles, fat-free milk, lemonade. Popsicles for dessert.
Despite this being the complete opposite of the diet that I want, I politely ate most meals. Suffice it to say that by the end of the second night I was in distress, with headaches and diarrhea. I snuck into the kitchen when nobody was around and looked for some butter, olive oil, any kind of fat, but there wasn't even any in the house.
The mom (who is a lovely friend of our family) seems to have bought into the "conventional" diet wisdom, with a vengeance. All of the food in the house is free of fat, mostly free of nutrients, mostly processed, and with lots of sugar. Her doctor recommends a "low fat" diet so this is exactly what she does. It was horrible!