image from Getty by Malte Mueller

I'm not exactly a New England Patriots fan. It's not that I really have anything against the Patriots, aside from my vague annoyance that the past decade of Super Bowl games has started to look a bit repetitive thanks to Tom Brady and Bill Belichick. In fact I'm only an NFL fan in the most generous application of the term—that is, I am usually in the room during peak football season when my husband has commandeered most of our illuminated screens in order to display as many concurrent games as possible.

But I do tend to read more than the average person, and I'm also the sort of person who has that peculiar fondness for the burn of marathons and other endurance sports. So when I read about The TB12 Method, a diet and fitness book released last year by a man who manages to regularly eviscerate his more-than-worthy opponents even at the relatively ancient (in football player years) age of 40, I thought it might teach me something applicable to my own health and fitness goals.

As far as sales go, the phrase "roaring success" isn't inaccurate. It became a New York Times bestseller and still holds the #1 bestselling spot on Amazon for Sports & Outdoors. It received pretty good reader reviews too, and—perhaps most importantly—Brady's strict dieting and stretching regimen does appear to lend to his mind-boggling longevity, agility and strength.

So I certainly can't fault him for sharing (albeit with the help of ghostwriter Peter Smith) his success with the rest of us who will never be five-time Super Bowl champions. Plus, a lot of what the book says jibes with other fitness advice you run into: Cut down on caffeine, alcohol, processed foods and other delicious vices; stretch like it's your job; drink more water; eat more whole foods and fresh produce.

But many of the reviews—from the New York Times' characteristically sober overview to SB Nation's biting smirk—pointed out that the science behind the book wasn't entirely, well, scientific, especially for a book full of claims that you would think needs to rely fairly heavily on chemistry and biology. It wasn't all wrong, and his advice will almost certainly make you healthier (except maybe for the hyponatremia-inducing total avoidance of sodium), but as sources including Vox noticed, "There’s no good scientific evidence that the diet does the specific things Brady claims—neutralize the body’s pH level or improve muscle recovery."

Does that make it an unhelpful self-help book? Not at all. Plenty of people may find health benefits in Brady's recommendations, and it has certainly been successful. Mission accomplished.

But, if you're a writer interested in composing your own self-help, fitness, motivation, or otherwise advice-based book—and particularly if you're not a globally-recognized pro football player whose face and name alone can sell thousands of copies—I'd advise that you make sure your claims are fact-based and appropriately backed by reliable sources and research.

Here are a few research tips to ensure that your work holds up better against a critical eye than this one did:

If you're writing a self-help book, you surely have knowledge to share on the topic of your choice. But there's a distinct difference between backing up your claims with fact-based evidence and relying upon personal anecdotes to tell your story. Anecdotal evidence is gathered informally—from your limited experiences, stories you've heard, etc.—while fact-based evidence relies upon sample data and thorough research.

Much of the evidence that Brady cites in his self-help book, for example, is based on his own success with his diet and exercise plan. That doesn't make the information untrue, or even unhelpful, but it isn't backed by statistics or scientific studies, and therefore there is no guarantee—and, indeed, no data sample to support—that the results described in the book will be those that every reader experiences.

Leveraging well-researched information and data instead of anecdotes will lend your book more credibility, improve the consistency of results for your readers, and ensure that it holds up under scrutiny.

Examples of anecdotes vs. empirical (fact-based) evidence:

Anecdote: "The participants in my yoga class found that the routine improved their balance, posture and peace of mind."
Empirical statement: "According to a study from the National Center for Complementary and Integrative Health, people with chronic lower back pain had significantly less disability, pain and depression after practicing yoga for six months."

Anecdote: "Author Samuel Smiles ones said, 'he who never made a mistake, never made a discovery.'"
Empirical statement: "Research by Stanford University professor Carol Dweck suggests that helping children acknowledge their mistakes while praising them for their efforts results in improved test scores."

Research Tips for Writing Nonfiction

Alex Guerrero, Brady's "body coach" whose methods provided the basis forThe TB12 Method, has been investigated by the Federal Trade Commission twice for making claims about his health products that turned out to be unsubstantiated.

If you plan to use one or more experts' advice as the core of your book, that advice needs to hold up to rigorous analysis. You'll want to carefully examine their credentials, history, body of work and their own sources that led to their conclusions. Ideally you would want to include information from more than one expert. If you're interviewing ann expert, make sure to ask for the research or evidence behind her claims.

If you are your own expert—e.g., you have an advanced degree in your field of study and have conducted extensive research into your topic—call upon peers whose work has preceded or complemented yours for supporting opinions.

Qualities to look for in experts:

Using the insights of a person whose questionable products have landed him in hot water with the federal government is one thing, but leaning so heavily on that one person's expertise is like building a house supported by a single (precarious) pillar.

If you want your thesis to hold up against critical assaults, it's best to make its supports as stable as possible, and that means using different types of sources that all point to the same conclusion. Blend a robust collection of primary and secondary sources for the best results. This approach can also add interest to your overarching narrative.

Here are a few different kinds of primary sources:

And a few examples of secondary sources:

When making empirical claims, make sure that someone else researching the same topic would find the same information by using reliable, independent data sources. Government agencies, educational institutions, hospitals and global research organizations are good places to start for facts, statistics and data.

Note that many studies by for-profit companies, think tanks and activist organizations cherry-pick data, which can result in misrepresentation of data and unsupported conclusions, so be sure to take a look at who funded the research as well.

Recommended data sources to use when writing a self-help book:

Business & Finance:

Motivation & Psychology:

Health & Fitness:

Parenting:

Faith:

All-Purpose:

Once you have the research, interviews and base information for your book together (or as you're assmbling it), make sure to fact-check. Here are a few fact-checking strategies that I've used in investigative journalism work in the past.

Fact-checking tips:

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