First lets actually break down that question into 2 parts…

What constitutes a diet and What do we mean when we say “work”?

Technically, a diet is just a way of eating, but for the purposes of this blog I will say it’s a way of eating that results in weight loss, if thats the case then almost all diets work.  The best diet is the one you can stick to long enough to lose the weight you want to lose.

I will go through a few popular ones here and list what makes them work

Keto= caloric deficit

paleo=caloric deficit

intermittent fasting= caloric deficit

IIFYM/macro tracing=caloric deficit

clean eating= caloric deficit

(vegan/vegetarian can also put people in a caloric deficit however because those two diets can have a moral component I m chosing not to include them here)

Let me be clear, if in fact your only goal is rapid weight loss then use whatever suits you. HOWEVER, I would encourage you to first ask yourself how frequently you find yourself trying the find the perfect diet.

Now for the second part of this question what do we mean when we say “work” THIS IS A VERY IMPORTANT PART OF THE QUESTION. One definition of “work” in this sense may be did it cause weight loss. Another definition of “work” may ask did it help you lose weight in the most optimal or healthy way with the least amount of suffering. While another definition of “work” might ask, were you able to maintain the weight loss for a period of  year or more.

As, a long term weight loss coach, I believe the best method and “what works” is the diet that causes weight loss with as little damage or suffering as possible and one that can be maintained for a year or more.

So to answer the question what diet is best…

The diet that is actually is best is the one that you can adhere to over time.