If you're like many Americans, you spend a lot of money to get diet and exercise advice, despite the fact you have no clue which nutrition and exercise advice is actually best for you.

But generic advice from a book or an article or a personal trainer at your local gym who gives everyone pretty much the same tips doesn't help -- and means you don't get the result you hope for.

Here's one example: "If you're trying to lose weight, it's okay to eat everything in moderation."

And that may even be true if you carry certain genes... but not others.

The key, of course, is to know how your body is made -- and therefore what is best for you.

Professional athletes have long followed highly personalized diet and training plans since they have access to results from genetic analysis and sophisticated diagnostics. Now some companies offer DNA testing for the rest of us, yielding data that can help you optimize your diet and fitness training, based not on feel or hunch or trends...but on what is truly best for you.

One is FitnessGenes, a service I've used and written about before -- including what I learned and what changes I then made to my diet and exercise -- that was founded by entrepreneur/doctors Dan Reardon and Sam Decombel.

The team at FitnessGenes just published a study showing the effect of the fat mass and obesity associated gene (FTO) on people who carry it. (FTO was the first gene found to be associated with human body mass.)

Those individuals are wired to eat more and feel hungrier more quickly. The FTO gene was once a survival adaptation, but is problematic in today's world where access to high energy foods is easy.

So what does that mean? First let's take a step back. Losing weight is obviously a real challenge for millions of people. Keeping off the weight you've lost is hard, too. Studies show the most common reasons for people to regain lost weight are:

  • Decrease in leisure-time physical activity
  • Decrease in dietary restraint
  • Reduced frequency of self-weighing
  • Increased percentage of energy intake from fat
  • Increased disinhibition (basically decreased impulse control and poor risk assessment where certain behaviors are concerned.)

Makes sense, right? If you're less active, less conscious of what you eat, don't monitor you weight, eat too many fatty foods, and give in to your impulses -- all the while disregarding the effect those things have on your health -- you'll most likely gain weight.

So you would think that people with the FTO gene would be at even greater risk -- but you'd be wrong. The study showed that within their population of physically active customers:

  • FTO did not increase BMI, waist circumference, or-waist to-hip ratio
  • FTO carriers showed better cognitive restraint in food choices - they were better able to avoid
  • Female carriers showed altered food disinhibition
  • Male carriers showed more vigorous physical activity
  • And on the flip side, reduced physical activity and greater disinhibition increased the probability of obesity

What does all that mean? Even if your genes give you a greater predisposition to obesity, there are things you can do to prevent or manage that tendency... as long you know what those things are.

That's where the importance of understanding your genetics comes in -- both for practical and emotional reasons. Instead of seeing the FTO gene as an excuse to be overweight, respondents said that since they perceived the gene test result as scientifically objective it lessened some of the emotion attached to the issue of weight control. In short, those struggling with weight control reported they felt some degree of relief from self-blame.

After all, if you're overweight it's not because you lack willpower, or lack something that other people have... you just haven't learned the right things to do for you.

All of which takes us back to that "eat everything in moderation" advice.

I'm an FTO TT: that means I don't carry the risk variation, and with it a number of dietary recommendations for weight loss, sports performance, etc, compared to the people who do carry the risk variant.

If you carry the risk variant, there are a number of things you can do in order to maintain a healthy body composition.

  • Eat more frequent meals to manage your hunger. Don't eat fewer meals. Don't skip breakfast. You're predisposed to feeling hungry -- don't make it worse. So eat more frequent meals, but...
  • Calorie-control your diet. Eat frequent, smaller meals.
  • Don't follow an extremely low-carb diet. People with the FTO don't experience satisfaction from low-carb diets... and if you don't feel satisfied you'll be tempted to eat more.
  • Do follow a low-fat diet. That will help control your energy intake.
  • Avoid junk foods. Junk food can stimulate negative behaviors. Junk foods are "high energy" foods, and that's the last thing your body needs.

In fact, according to Dan, "Having the FTO gene variation and consuming high energy foods, even in moderation, could in some ways be equated to an alcoholic consuming alcohol in moderation -- the long-term outcome would likely be poor."

That's why generic advice only provides generic results. Following the right nutritional habits for you will make a much greater contribution to long-term weight management than generic advice like "eat everything in moderation," especially if that approach actually stimulates negative responses.

And that's the best part of genetic testing for health and fitness purposes. We tend to make decisions about our bodies based not on science or data... but on what feels right or what feels easier. As with most things, doing what we want to do usually doesn't provide the same results as doing what we need to do.

You wouldn't dream of running your business that way -- so don't run your body that way.