this would be a great study tip if it wasn't so inaccurate! As a type one diabetic people using blood sugar as a buzz word really frustrastes me.
Nuts have around 10g of carbs per 100g (the stuff that regulates your blood sugar) which is next to nothing. It's a great snack if you're trying to lose weight because you can eat a lot without gaining that much (carbs = slow acting sugars = energy, energy in>energy out = weight gain) but will not help you with keeping yor energy up.
Raisins on the other hand have around 80g of carbs per 100g, meaning if you need a spike of energy raisins are a great way to go! And much better for you as more nutrients than having an energy drink.
Bananas are 30g if carbs per banana so this is an excellent in between, it won't cause you blood sugar to spike and crash (due to fat content and other stuff) but it also has enough carbohydrates to be substantial
Oats are slow releasing! But granola bars that have loads of honey in them will be much less so!
APPLES ARE NOT SLOW RELEASING CARBS!! fruits are full of sugar, one apple has 16 grams of sugar in it. Not carbs, fast acting sugars. They are full of nutrients but other than that you might as well be eating a chocolate bar. There's not such thing as 'healthy sugar' there is just sugar which you need to eat, but ration. You're body does not distinguish between apples and red bull in terms of blood sugar!
I would personally recommend eating some starchy carbs before sitting down and topping then up. I have a couple of slices of toast (just butter no jam or honey) and in my breaks I'll have a handful of nuts, or if I'm getting tired a biscuit.
And all those studyblrs out there: stop pretending you're nutritionalists, stop using buzz words without doing the research, stop giving bad advice because it sounds accurate enough!