Real talk: I don't love snacks.
When I write meal plans for my nutrition clients, I urge them to consider two or three amply-sized meals, or two meals and one decent snack, rather than a bunch of bits & bobs of food or small "snack-like" meals all day long (hint: if you sit down to a meal and the ENTIRE thing adds up to fewer than 300 cals - that's what I consider "snack-like" - not really a meal).
It's not that I never have food between meals, or think that all snacks are unhealthy, but here are my three main issues when nutrition clients ask me about snacks:
1) Things folks usually eat as snacks (nuts, fruit, cheese & crackers, chips, granola bars) are usually void of protein - taking up calorie space that would be better allotted to...protein*.
[*for more on why this is an issue for those trying to lose weight, read more about the protein leverage hypothesis]
2) People are generally less good at estimating the calorie totals of their snacks (read: they either underestimate the portions or forget about the snack altogether, thinking "oh, it was just a small thing..." - until their snacks end up derailing the day calories-wise)
3) Avid snackers tend to undereat at their actual meals (if you've ever observed a toddler eat, you will know exactly what I mean - they can plow through half a bag of Goldfish but somehow have "no room" for a bite of chicken or broccoli at lunch) - leading to more snacking...
And hey, I'm not alone in being a snack-hater - scientific studies show that for people with Type 2 diabetes (you know, the sugar-related one) - two large meals versus six small ones can actually improve insulin sensitivity - which leads to better glucose response and an easier pathway to fat loss.
There's also a decent amount of research which shows that people who eliminate snacking have an easier time losing weight, since it generally encourages caloric deficit.
But what if snacks are life? Ok, ok, I hear you.
Some folks were made for snackin', and snackin's what they'll do - so here are some simple guidelines on how to do it better:
make sure your snacks contain at least 30% protein (something like Greek yogurt with almonds, tuna on cucumber slices, a quality protein bar, or beef jerky will fit the bill)
double up the nutrient power of your snacks by choosing high-fibre complements to your high-protein snack choices (add raspberries to your cottage cheese, roll some turkey slices into a low-carb, high-fibre wrap, or dip broccoli in Greek yogurt tzatziki)
plan your snacks the way you plan your meals, so the calories are accounted for as part of your whole day (and not just "tacked on" to an otherwise healthy meal plan)
take 500mL (16 ounces) of water down with each snack you do choose, to ensure you're not mistaking dehydration as hunger (fixing the "wrong" problem, I always say)
Whether you choose to snack or not depends greatly on differences in lifestyle, time constraints, family schedules, body composition goals (those looking to put on muscle mass may actually have to add snacks to their regular meals!), low blood sugar response, and of course - preference!
But whether you choose to snack - or hold back - when weight loss is your goal, any strategy that gets you to a consistent caloric deficit will help you find success.