Grade A is okay. I can get grade B, But I get medium amber A from Costco/Price Club in California. Canadian, 100%. I don't notice a ton of difference and the price is, get this, less than $13 for a 1/2 gallon. I'm not rich, so this suits me just fine. If you have a Trader Joe's around you can get good B for about $17 a quart.
After all, a fast is undernutrition, and the weight your body loses is because it's eating itself. And guess what, it gets the nutrients it needs that are stored in your body. Many people have fasted over 40 days on water, and those in concentration camps who had a positive attitude too who were underfed for years. Their blood panel results were better than probably any of us. Sometimes I think we make this too difficult. I'd do grade A for a couple months and match my blood profile with anybody.
Mike D.