What are the best snacks to eat during the day?

Snacks really should be considered meals, so I suggest make sure you hit all the macronutrients- carbs, protein, and healthy fats. As to what in particular it depends what you do during the day. Carbs can be fruits, veggies, whole grains and as a vegetarian I am often combining healthy fats and my protein with nuts, nut butters, and legumes (mmm... edamame!).

I suggest fresh, whole foods as much as possible. This is feasible with a little planning and a soft-sided cooler with re-freezable ice if you're on the run. Pairing a healthy fat or protein source with a carb source can be satisfying. Examples might be whole fruit such as apple, clementines, or pears with string cheese, raw almonds or natural peanut butter; non-fat Greek yogurt with berries and walnuts, sliced turkey or cubed chicken with salsa wrapped in romaine lettuce or whole grain pita, raw veggies and hummus, packet of tuna with cherry tomatoes, hard-boiled egg whites, etc.

I would suggest skipping the snacks. I think it is more important to eat meals and structure them to eliminate snacks. Snacks is where people tend to cheat there well structured meals full of important macro and micronutrients. I suggest spreading out meals, even if it requires breaking them up into smaller portions to provide satiety throughout the day.

Good healthy snack are fruits , vegetables , and nuts.

Whole foods are a great choice.

I have an awesome snack that incorporates you lean protein and carbs, and it's veggie full and yummy! My kids love it as it's a new spin on an old classic
Celery stalks, washed and cut in 1/2
1 tablespoon natural peanut butter
1/4 cup non fat greek yogurt
1/2 scoop natural whey protein (vanilla or chocolate works best)
1 tablespoon raisins

Mix pb, yogurt, and protein until it makes a fluffy mousse.
Spread on celery and top with a few raisins
Ants on a log redo!
Serves 4 people.
Mousse will keep in fridge for up to 3 days

greek yogurt, cottage cheese, rice cakes, 1 tsp peanut butter, almonds to name a few

Fruit and nuts/cheese in the am and veggies and nuts or cheese in the afternoon - all organic. If you are avoiding dairy switch your protein to chicken if you are not eating nuts. If you are eating nuts remember they are a high-volume food which means they are high in both calories and fat so easy on your portions - no more than 10-12 almonds for example. Be sure to balance your macronutrient profile to make sure you are getting a good balance of protein, carbs and fats throughout the day and not over-carbing or over-fatting or, for that matter, exceeding a calorie intake that matches your goals. Have your fruits consumed before noon when you need the carbs for energy.

Fresh, whole foods as much as possible. Remember, though, that when you have a snack or meal, that you should include a lean protein, a complex carb, fiber, and healthy fat. Your body needs all of them to function properly.

Always have fruits and veggies on hand. Have them cleaned and prepped and ready to go. Hummus is also a great snack with veggies. Nuts, beans, roasted chick peas, and yogurt.

I tend to eat fruit, nuts, sometimes a peanut butter and jelly sandwich, fresh squeezed vegetable cocktail. I purchase whole grain crackers and spread taramarsalata, tahini, or humus on it. It depends.

I don't like to say best snack because it think it is subjective to one's tastes and culture.

Natural peanut butter, fruits, seeds, whole wheat bread/bagel with salmon OR tofu to name a few. I always try to eat just before and after a workout and DRINK plenty of water too.