Lately, I find myself thinking a lot about one of Warren Buffett’s most famous quotes…

“Investing is simple, but not easy.”

The idea is that the rules for investing are fairly straightforward.

You don’t need a degree in finance to understand the basic principles, and they don’t change all that much.

The challenge is actually getting yourself to follow them.

Over the holidays, I was driving across Ireland and talking to a smart friend of mine about this concept.

In trying to explain it to him, I used the example of a popular New Year's resolution — diet and exercise.

Following the Financial Food Pyramid

At this point, we all know the basics of having a healthy diet and an exercise regimen.

A good diet consists of healthy fruits and vegetables, lean proteins, and superfoods like legumes.

It’s also important to eat in moderation and have a diversity in our diets.

And what you don’t eat is just as important as what you do eat. Sweets, processed foods, saturated fats, and alcohol.

If you want to know more about the science behind it, you can read up on how diet impacts our glycemic index or cholesterol production.

But if you only know these basic guidelines, that’s enough.

Exercise is similar. Regular cardiovascular activity, along with weight training to build lean muscle mass, is good for health and longevity.

Again, we all understand this.

So if these basic principles are well known and rather simple, why do so few of us accomplish our diet and exercise goals?

As Buffett says about investing, it may be simple — but it’s not easy.

The reality is that many of the foods and drinks we shouldn’t consume are some of the most enjoyable.

Our bodies are biologically developed to deal with a world of food scarcity, and they still respond to those ancient signals.

The evolutionary wiring that enabled human beings to survive and prosper over hundreds of thousands of years now makes it difficult for us to maintain healthy habits.

The best way for us to do it is to create routines and processes around our diets.

A healthy diet should consist of a regular schedule, fresh ingredients, moderate calorie intake, and enough vitamins and minerals.

It can even include a delicious treat every now and then.

These same rules can be applied to investing:

• It’s good to have a regular schedule for contributions to your retirement accounts to make sure you do it consistently.
• The “fresh ingredients” are high-quality, high-growth stocks.
• Buying stocks at reasonable valuations (or with good chart patterns) is the investing version of caloric moderation.
• It’s incredibly important that you regularly measure your portfolio’s performance. Optimizing your winners and minimizing your losers.
• Don’t be afraid to have fun sometimes. It’s ok to take a flyer on a momentum stock or an options position, as long as it’s the right size for your portfolio.

No, these rules may not be easy to follow. But they are simple.