About 40 grams of clean protein (soy, lean beef, fish, chicken, turkey) and about 30 grams of slow carbs (think oatmeal, farina, grits, or even rice) should do nicely. You can eat up to, during, and immediately after, exercise. There's no value added in delaying meals. Juice isn't a very good choice because the sugar causes an insulin spike just at the time you don't want it, causing a blood sugar crash, and would be ill advised.
If you find yourself dragging, one solution is corn starch, apple juice (a bit slower) and protein, while you work out. It's cheap, and it's effective. There's no reason you can't eat while under load. If you can, though, it's generally easier to refuel in the golden hour post-workout. That's a time when you DO want fast sugars to reload your glycogen.
If you restrict calories, your body's metabolic rate will slow in the "famine response" which probably isn't what you want. You need to "fuel the furnace" by eating properly, and by avoiding metabolic lag. A fueled furnace burns hot, and you'll have better results if you eat.
Staying lean is not so much about calorie restriction as metabolic activation. You need to EAT to be able to be active in a way that supports lean muscle mass and fat burn.
You'll want to be sure to incorporate weight training / resistance training into your fitness program as it strengthen your bones, increases your lean muscle, and increases your metabolism as YOU GROW OLDER. No other exercise does that.
If you restrict calories, you'll lose lean muscle, and burn FEWER calories, and have a SLOWER metabolism, and be lethargic. That's likely not what you wish for. You'll want to keep your calories UP, train HARD, LIFT, and EAT.
There's rarely a strong case for being deloaded as your performance suffers. Best to eat, and UP your intensity, instead.
You'll want to do exercise specific to your chest and shoulders to avoid the typical very unbalanced musculature of a swimmer.