If  you’ve paid attention to health and fitness in the last few years, you’ve no doubt heard about the Paleo diet. Loved by Crossfitters, casual lifters and even a few bodybuilders, the “caveman” diet is often touted as the best path to health, wellness and weight loss. Its supposed health benefits have even led some trainers to advocate its use for bulking up and gaining mass and strength.

Is the paleo diet really the miracle some claim it to be? Not quite. While its strictest adherents would have you believe grains and dairy are the devil, the truth is that eating like our ancient ancestors is a totally arbitrary idea. If anything, we should NOT seek to replicate the habits of cavemen, most of whom suffered malnutrition, frequent infections and early deaths.

That said, the paleo diet is a pretty good way to eat! Despite the diet’s valid criticisms, most people who stick to it are relatively lean and healthy. Problems arise, however, when paleo dieters fail to understand the reasons behind their success – and when strict adherents continually fail to achieve their goals. Here are my thoughts on the positives and negatives of the Paleo diet.

Good – Eating Whole Foods

In its purest form, the paleo diet has adherents eating strictly whole, unprocessed foods. Pretty much any meats and veggies are fair game, as well as nuts, seeds and natural oils. These foods are the basis of any good diet! Eating this way, it’s hard NOT to get plenty of protein, healthy fats and vitamins and minerals.

Bad – Fear of Carbs

According to most Paleo experts, any and all grains should be avoided. Their rationale is that humans haven’t evolved much since the dawn of agriculture, and our bodies weren’t made to handle the starch and other nutrients present in wheat, oats, barley and other mass-produced crops. This idea isn’t just lacking scientific backing – it’s actually detrimental to athletic performance.

Grains serve as our main sources of carbohydrates, the fuel any lifter needs for intense, heavy workouts. Sweet potatoes and fruits are allowed on the Paleo diet, sure, but it’s tough to eat them in the quantities we really need for peak performance.

Making matters worse is many Paleo dieters’ fear of carbs, even those allowed on the diet. High-fat, low-carb diets are common in the Paleo community, and while they can help some people lose weight, they’re not going to fuel intense workouts. Bottom line: If you want to be lean, muscular and strong, you need your carbs – and you’re probably going to need to get them from grains.

Good – Plenty of Produce

One big advantage the Paleo diet has over the traditional bodybuilder diet is its focus on fresh produce. With fewer sources of starch and sugar to eat, Paleo dieters tend to fill their plates with simply prepared fruits and vegetables. Do you need to avoid grains in favor of produce? Definitely not! What you should do, however, is eat a colorful variety of vegetables every day, no matter your current dietary goals.

Bad – Elimination of Dairy

Some people can’t digest dairy very well, but the Paleo diet outright restricts its consumption. That’s a shame because milk products can be excellent sources of protein, particularly for vegetarians. Higher fat dairy like whole milk, cream and butter can even be good for skinny guys trying to gain weight. Avoiding dairy also means eliminating whey protein from your diet – one of the best foods to eat for intra- and post-workout recovery.

Good – Quality Proteins

Every budding bodybuilder understands the importance of protein, but far too many lifters rely on protein powders, chicken breast and egg whites. Those are good sources, to be sure, but they lack the micronutrients, healthy fats and overall calorie content required to get big and strong.

On the other hand, the Paleo diet tends to emphasize a wider variety of proteins, including steak, whole eggs and fatty fish. These aren’t necessarily the best sources for someone trying to lose fat, but for a lifter who’s training hard and trying to put on muscle, they offer far more bang for the buck. Plus, they taste better!

Bad – No Legumes

In addition to grains, Paleo demonizes another great source of both carbs and protein – legumes. These include beans, peas, lentils and every bodybuilder’s favorite, peanut butter! The logic against their consumption is essentially the same as the anti-grain logic: Legumes are a product of modern agriculture, and our bodies cannot digest them properly.

While some people do experience gas and bloating with some legumes, avoiding them altogether is pointless. Beans and lentils are excellent bang-for-your-buck foods that pack lots of starch, fiber, protein, potassium and other essential nutrients. They’re especially helpful for vegetarians and low-budget bodybuilders, since they can supplement your protein intake at far lower prices than meat.

Good – Automatic Calorie Reduction

Like any successful diet, the Paleo diet works for weight loss by reducing calorie consumption. Adherents are adamant that cutting out grains, dairy and sugar is what made them lose weight, but what really happened is that avoiding those foods led them to choose less calorie-dense alternatives. If you replace all of your processed snacks and sugary drinks with meat and vegetables, you’re bound to lose weight!

Bad – Not Paying Attention to Calories

On the other hand, there are plenty of people who don’t lose weight on the Paleo diet. In fact, some people even get fatter! Instead of tracking calories, they simply choose foods that are allowed within the scope of the diet – and that includes high-fat foods such as eggs, avocados, coconut oil, bacon and fattier cuts of beef. There’s nothing inherently wrong with these foods, but there’s nothing magical about them, either. If you don’t consume fewer calories than you expend, you won’t get lean!

Really Bad – Dysfunctional Eating

As much as I criticize the Paleo diet, it’s not a bad diet for people looking to lose weight – as long as they take the time to track calories. My biggest beef, however, is that it results in some seriously dysfunctional eating. I’ve seen Paleo dieters claim all sorts of food allergies and intolerances that have never been diagnosed, and they’ll go way out of their way to avoid social situations with “normal” food.

Ultimately, I favor a more flexible approach. Whether you’re trying to get lean, get big or just maintain, your diet should consist of mostly unprocessed lean proteins, starchy carbohydrates and healthy fats, along with plenty of fruits and vegetables. Sensible calorie consumption and exercise habits are what really make for a healthy body and mind, and obsessing over arbitrary rules will only lead to wasted time, money and mental energy.