The midday crash might be helped by a helping of water. that tiredness or lack of concentration is probably dehydration. make that water at the optimum temperature that makes you the most energized. my ideal temperature is just above freezing so I laden my water down with ice.

The crash will probably go away or diminish a great deal during the first couple weeks of dieting, but may slowly return.

If you are not addicted to nuts, I'd suggest packaging up some nuts of your choice for a snack with water. yeah there are carbs in nuts. pick almonds, walnuts, or macadamias, and you'll find a good balance. say no to peanuts, please (they are not nuts). if you particularily like cashews, pistachios, or pecans, then only take a few (you know, 3 or 4 nuts). 20 almonds is roughly equal carbs to 4 cashews.