Like I said, the answer to this question is not at all simple. It all depends on several factors such as your training level of expertise (this is key), the type of training you will undergo, and the competency level of your coach/trainer (this is also key).
You have probably heard from some coaches who refrain from using the belt because it gives the trainee “a false sense of security”. I partly agree with this, but again it depends on the above situations I have noted (training level, type of training, coach). For instance, if you are new to working out, and you’re still working on mastering your form for the Deadlift for example then I would say – please stay away from the belt. I say this so strongly because it is really important that your body learns how to utilize components of itself during lifts. That is, when you’re doing such lifts you need to learn how to activate your core/abdominal muscles (especially your oblique and transverse abdominals) and use them to ensure that your lifts are stabilized. In other words knowing how to do “the core squeeze” with every lift is an essential component to your training. If your novice self uses a belt you will be more prone to injury and that’s where the “false sense of security” comes in. You will have a “false sense of security” because you will probably be lifting heavy without using your core which would most likely result in a back injury. To be blunt, if you always use the belt and can’t even conduct a lift without one, then you’re using a belt to hide your weak core- be humble, strengthen your core, and turn to reasonable training progressions until your core is stronger.
Now, even when you become a pro (great form, great muscle activation etc), I still advise my clients to warm up and do lighter reps without the belt. Doing so will allow you to progress on your path of continuous motor learning and core strengthening. Personally, I only use the belt when I am working on a lift which is at least 85% 1RM in other words I do not use the belt for anything less than 270lbs. All that to say, if you’re a pro (like seriously you are) then the belt can help you during heavy lifts and potentially help your performance reach to the next level- I found this to be true with my rack-pulls. Some research indicates that when you use the belt, you allow for your spine to be stabilized making room for a safer heavy lift. Remember how I mentioned a competent coach – yes a competent coach will ensure that you learn how to properly activate/engage your core during a lift, stabilization etc before s/he makes you use a belt “just because”.
Keep in mind that there are 3 most popular belts: Bodybuilding/traditional, Velcro, and Powerlifting. When I tried the bodybuilding belt it was too thin for my liking and I didn’t feel as much support in my back. The Velcro belt has a bit more pressure than the traditional belt but it was always annoying having to re-tighten and re-adjust the belt when it became loose. Powerlifting belts are my favourite. Although they are usually very stiff, they are equipped with a buckle which essentially allows for you to tighten the belt to your preference. The one that I have typically creates an increased intra-abdominal pressure (than the Velcro which can just snap off with too much pressure) which allows for my lifts to be more stable when I lift heavier. Please note that if you have issues of blood pressure or a history of hernias double check with your health care provider if these are safe for you. There are specifics to the differences in belts that I have not covered here (because that wasn’t the point of this) but feel free to send me an email (email@example.com) and we can talk about it.
So in conclusion, unless you’re a serious lifter, you do not need to use the belt. Learn how to engage your core and work through effective training progressions to get you stronger!