Often when people start a new diet, they struggle to stick with it--for a number of reasons.
When it fails them and they "fall off" they decide they're failures or it just wasn't the right diet for them.
They start looking for the next one in hopes of maybe the next one with whatever stupid rules it puts forth will be THE one they can finally stick to.
I know because I've been there AND because I have 8 years of experience hearing other women tell me all the diets they've done in the past and how they hope I'll finally be the thing they can finally stick with (fwiw, that one line from new clients predicts with 100% accuracy who will not get past the first week or two successfully.. because it's a mindset that fails every time).
Anyway, I've read at least 4 different studies done in the last year ALONE that consistently prove when daily caloric deficits are equal--meaning everyone eats the same amount below their maintenance level (which is an important distinction)--no single diet reduces body fat (also an important distinction as body fat loss is not the same as weight loss) faster than any other. Keto, paleo, low carb, all those of fad diets with their miracle claims are flat out lying that they're the best, fastest, easiest, etc.
The REAL reason many people appear to lose 'weight' quicker on those types of diets (if they do) is because they're usually starvation level calories, thus making daily deficits higher (which as I've discussed at length is terribly unhealthy not to mention pretty much guarantees a huge weight rebound when you go off them). And also because less carbs can cause drastic water weight losses that will make the scale go down have literally nothing to do with how much fat is on our body.
On top of that because of all their insane rules they have a crazy high drop out rate.
The single biggest determining factor in fat loss is being in a consistent caloric deficit.
The truth is that our dieting woes don't exist because we don't know how to lose weight or because we haven't found that elusive diet that we can finally stick or will make us lose weight super fast, it's that:
we're not caring enough about or goals to eat in enough of a deficit consistently enough to see the results we want
we have no idea how much is going in so we may think we're doing everything right and following whatever "diet" we're on perfectly but we're not actually in a deficit
we eat and gain weight for sooo many different reasons that trying to fix them with temporary diets and strict rules is like trying to fix a bullet hole with a bandaid. It may stop the bleeding for a hot second but it's going to come pouring back out when the bandaid can't cut it anymore.
We don't need more new and ridiculous ways to try to lose weight.
We need to work on why we gained it in the first place, the mental clutter that's keeping us stuck in it, caring enough about ourselves to know we're worth the effort and we need to make the decision that we're doing it until ...because that shit is ugly, haaaard and takes time. We need to slow down, be present, get mindful and connect with our bodies in a way that allows us to start listening to them and giving them what they need.
Yes, food choices definitely matter and no, not all calories are created equal in regards to looking and feeling our best but weight loss doesn't require any special knowledge or rules beyond just knowing how much is going in and how much you need.
So, if you know what you need to do and you consistently don't do it, it has nothing to do with food or diets. There's an underlying issue or story about yourself that keeps playing out. When you identify that and work on rewriting it, you'll be successful.