Eating smarter will help you hit your health and fitness goals faster – but which diet is the ideal one for you? Coach’s sister title Men’s Fitness assesses the evidence and asks the experts so you can make the right nutritional decisions.

The Theory

A way of eating based on only eating foods that would have been available to our caveman-era ancestors, based on the idea that our modern diet – full of trans fats, refined carbs and easy-access sugar – is to blame for everything from cancer and Alzheimer’s to depression and infertility. Fruits, vegetables, meat, nuts and seeds are all on the menu, while dairy, sugar and starch are off. The most argued-over omission? Grains and legumes, which many Paleo advocates say contain “anti-nutrients” that can block the absorption of minerals and vitamins, as well as causing digestive issues.

The Evidence

Reasonable. Several studies comparing Paleo with a typical American diet have linked it to increased insulin sensitivity and improved lipid (body fat) profiles – and a 2016 paper linked the diet to reduced inflammation, something often thought to be associated with cancer. Then again, almost anything’s better than a typical American diet.

The Good

Getting more protein, veg and healthy fats is no bad thing, and cutting out sugar’s unlikely to do any damage. Tackle Paleo properly by eating grass-fed, free-range meat, and you’ll benefit from its improved hormone profile and omega 3:6 ratio. Oh, and it wouldn’t hurt to eat some vitamin-packed offal occasionally.

The Bad

Paleo fans are largely backing away from the “our slow-evolving bodies haven’t adapted to agriculture” argument that helped launch the movement, because it probably isn’t true: there’s decent evidence that different populations have evolved to eat the foodstuffs cultivated over the past few thousand years.

Similarly, the Paleo-approved foods available in your local Sainsbury’s don’t bear much relation to what a caveman ate – everything from asparagus to yams has been selectively bred for size and taste, sometimes at the expense of nutrition. And not all Paleo dieters make a distinction between processed and unprocessed meat – not ideal, since the WHO has linked processed stuff like bacon and sausages with a slightly increased cancer risk.

The Expert Verdict

“What I like about the Paleo diet is that, at its core, it advocates cooking from scratch and shuns overprocessed foods,” says nutritionist Yolanda Hinchcliffe. “It also promotes local and seasonal foods and sustainably raised proteins. I think it’s a good basis for a diet – but watch out, because it can become too restrictive. And eating to a guideline rather than listening to your body’s needs isn’t the best way.”