There's a famous quote from Tolstoy that goes: "All happy families are alike; each unhappy family is unhappy in its own way."

Well, it's the same with nutritional programs. However different they might look on the surface, the effective ones are more alike than they are different.

Meanwhile, every unhealthy diet is unhealthy in its own way.

How can a diet be bad? Let me count the ways.

"Detox diets" are too low in protein, calories, and fiber.

The "Cabbage Soup" diet (and other restrictive diets ) can take the fun out of eating. Plus, any weight you lose will probably only be water.

Drastic measures like "ear stapling " are unproven and can lead to infections.

And the typical Western diet can lead to heart disease and diabetes. Not to mention obesity, which the AMA now considers a disease in itself.

In other words, every lousy diet is terrible in its own way. Although all lead to poorer health.

Five signs of a sane and healthy eating plan

While every bad diet is uniquely bad, good diets are a lot more similar than they might appear on the surface.

Wait a minute.

How can a meat-heavy diet be like a meat-free diet? How can a low carb diet be like one that's higher in carbs? How can intermittent fasting be like frequent grazing?

Actually, it's no real mystery. Because every sane eating plan will help you make five key changes. And these changes form the basis of nutritional health.

Let's take a closer look.

1. Raise your awareness of nutrition.

I know, everyone wants to talk about the food itself -- the proteins, carbs, and fats. What to eat more of and what to avoid.

But recent research shows that simply paying better attention to what you eat can help you lose fat, get lean, and improve your health.

Honest.

Whether you reduce carbs, eat more vegetables, source organic food, eat less meat, or eat more "ancestral" foods, it's all good.

Because what you focus on may not matter as much as simply caring more about what you're eating in the first place.

2. Focus on food quality.

Paleo and low-carb advocates want you to eat more natural, free-range animal-based foods. These foods tend to be higher in protein and fat. Plus, they are minimally processed.

Vegan and high carb advocates want you to eat more natural, plant-based foods. These foods tend to be higher in fiber and antioxidants. Plus, they are minimally processed.

Recognize what's common here?

Very few nutrition camps recommend you eat more processed, chemical-laden "junk" food. (Thank goodness.)

Instead, every sane nutritional plan recommends eating whole, minimally-processed, nutrient-rich foods. And that may be one of the most important interventions of all, regardless of the macronutrient breakdown.

3. Eliminate nutrient deficiencies.

Processing often strips much of the nutritional value from foods. So, by emphasizing whole foods, the best diets help us address nutritional deficiencies.

In fact, a well designed diet of any kind eliminates some of the most common nutrient deficiencies . (These include water, certain vitamins and minerals, proteins, and essential fatty acids).

This is huge. When we lack important nutrients, we often look, feel, and perform badly. But within a few weeks of correcting these deficiencies, we feel rejuvenated. (And because the transformation is so dramatic, that's often when we become diet zealots.)

4. Control appetite and food intake.

How so? Well, when we pay attention to what we're eating, eat quality food, and resolve nutritional gaps, we almost always eat less food in total.

We feel more satisfied. We lose fat, gain lean muscle, and perform better.

Notice that you don't need calorie counting here. Focusing on food awareness and food quality is usually enough for people to tune into their own hunger and appetite.

And that means calorie control without the annoying calorie math.

It also means more sustainability since counting calories has a shelf life. No one does it forever.

5. Promote regular exercise.

When people start paying more attention to what they eat, they usually pay more attention to exercise as well.

In fact, many of the diet camps recommend regular exercise. (Which is a good thing, since focusing on diet alone may actually interfere with establishing a consistent exercise routine.)

People who exercise are better at turning the food they eat into functional tissue (instead of extra fat). Especially if their exercise routine includes high and lower intensity activities.

And this is true, no matter what kind of diet they follow.

The bottom line? No single diet is right for everyone.

And really, how could it be? Not when you consider the differences between us.

From physiology to lifestyle, we're all facing different challenges.

And these differences can affect the kind of diet that will be sustainable and effective for any given individual.

Luckily, there are also many healthy ways to eat.

In fact, most of the best-known eating plans can help control appetite, improve food quality, promote exercise, and raise nutritional awareness.

So, if the nutritional plan you're considering does all that, it's likely a sane approach. Follow it consistently and you'll be well on your way.

Because, of course, there is no "Best Diet Ever." There's only the "Best Diet For You." And that may be different from the best one for your spouse, best friend, or workout partner.

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Want some help finding the best diet for you? Download this free guide: Paleo, vegan, intermittent fasting... Here's how to choose the best diet for you .

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About the author.

John Berardi, Ph.D. is a founder of Precision Nutrition , the world's largest online nutrition coaching company. He also sits on the health and performance advisory boards of Nike, Titleist and Equinox.

Dr. Berardi was recently selected as one of the 20 smartest coaches in the world by livestrong.com, the internet's most popular fitness site.

In the last five years, Dr. Berardi and his team have personally helped over 30,000 people improve their eating, lose weight, and boost their health through their renowned Precision Nutrition Coaching program.