Diet Advice: Sorting Good from Bad

How to find practical nutrition advice amid all the hype and BS

Whatever food you think is good for you, or bad for you, odds are you can find an article, video or podcast out there that touts it or demonizes it. Between the flip-flopping scientific findings and all the nutrition nonsense spouted by adamant non-experts, it’s hard to know what to eat.

“Calories and certain food groups have been vilified by diet culture,” says Joyce Patterson, a registered dietitian and diabetes care and education specialist at Michigan Medicine in Ann Arbor.

“With every new study, there is a new headline, causing whiplash among patients and health professionals alike,” says Patterson, author of the new book, Think Like A Dietitian. “Whether people are counting calories, carbs, fat, sodium, or other nutrients, the interpretation is often ‘less is more.’ Instead of focusing on healthy food choices and overall balance, some people get caught up in the minutiae of nutrients. They feel food is something to be avoided, as opposed to being the fuel that provides power, strength, and protection.”

In today’s diet-obsessed society, with all the marketed quick fixes and silver bullets, there’s an argument to be made for paying less attention to all the advice and, unless you have a medical condition that dictates otherwise, striving simply to eat real food. I’ll explain what I mean by real food after we consider…

Why nutrition science is so tricky

A chief reason diet and nutrition research is often vague and conflicting: It’s impossible to do a study in which everything people eat is tightly controlled for long periods of time, after which food-related health outcomes might become clearly evident. Instead, health outcomes or predictions based on diet habits often involve self-reporting, which is highly inaccurate, or short-term trials that control diets for a few days or weeks and extrapolate long-term possibilities.

And try as they might, researchers struggle to account for all the possible confounding health and behavioral factors that skew outcomes.

The result: inconclusive research, public confusion, and great marketing opportunities.

“We live in a world full of messages to restrict, eliminate, and fast, and misconceptions related to diet trends are common,” Patterson explains.

What we do know

The lack of perfect science does not mean we don’t have good information on what goes into a healthy pattern of eating, as well as what sorts of foods are generally unhealthy. But the state of nutrition research makes a great argument for hewing toward moderation, both in food types and overall calorie consumption.

Based on the body of research, we can state three clear facts that contribute to poor health but are all common problems today:

Eating too much is unhealthy, and most Westerners eat way too much. Most adults should take in between 1,600 and 3,000 calories a day, experts say (here’s a calculator). The typical US adult consumes more than 3,600 calories daily — a whopping 24% more than in 1961. Put simply, we overload the body and all its organs, leading to gas and bloating in the aftermath of a meal, poor sleep at night, and deteriorating physical and mental health in the long run. Learn more:

Plant-based diets can be the foundation for good health, adding years to the potential lifespan and healthspan of people on average. One flavor of this eating pattern is called the Mediterranean diet, which is not actually a diet but rather a way of eating. It involves leaning into nuts, seeds, beans, whole grains, vegetables and fruit, and consuming red meat in moderation. It emphasizes a variety of healthy foods and avoids ultraprocessed foods like hot dogs, salami and other packaged “food” that’s linked to heart disease, cancer, dementia and numerous other diseases. Learn more:

Ultraprocessed food is terrible for the body and mind. These so-called “foods” include many packaged cereals and other convenience items sold in boxes or frozen, as well as prepared meats and the oil-soaked junk peddled in fast-food restaurants. No longer real food, it’s loaded up with gobs of sugar and salt and countless unpronounceables to keep it fresh and pretty. A study published last month in the journal BMJ linked ultraprocessed food with higher risk to 32 bad health outcomes, including cancer, heart disease, mental health disorders and the biggie: death. Chew on this little nugget: Ultraprocessed food now represents more than 50% of calories consumed in the US and other industrialized countries. This crap is manufactured to be addictive, and we’re lab rats in the greatest “food” experiment of modern times. Learn more:

Beware the hucksters and even well-meaning diet advisers

Beyond those truths, if you’re seeking the perfect diet, start with a heaping helping of common sense. Superfoods aren’t super, they’re just food. You can’t live on blueberries or kale alone. We are not evolutionarily programmed to eat nothing but red meat, no matter what some supposed expert claims. Don’t buy into any scheme that claims there is one category of food you should eat exclusively (whether meat, veggies or anything else) or in extreme proportions of any kind, unless you’ve been advised by a doctor or nutritionist with intimate knowledge of your individual health profile.

Particularly suspect is any diet that generates income for whoever is hawking it.

In her book, Patterson busts myths and generally calls for moderation in food choices. Yes, she might make money on the book—which is aimed primarily at educating other dieticians and nutrition counselors—but she’s not trafficking in anecdotes, opinions or utter BS. She’s not selling supplements or shakes or secret plans. Oh, and she doesn’t want you to give up on nutrition science, just because it’s imperfect.

“The sheer number of products and programs claiming to ‘reset your metabolism’ or ‘cleanse’ your system indicates that many people are indeed interested in the science,” she says. “But few receive comprehensive and reliable nutrition education and are unable to discern between marketing ploys and good science. They are making food choices and purchase decisions based on minimal or misleading information.”

Problems with keto and intermittent fasting

Some diet schemes come out of nowhere and skyrocket in popularity, but not because good science suggests their worth consideration by most healthy individuals.

Case in point: Ketogenic diets have been shown to offer near-term benefits for people with diabetes and other metabolic disorders, and for weight loss in some people. It can help treat specific conditions under the direction of a physician, experts say.

But long-term research on effectiveness and health risks of this low-carb diet is lacking, Patterson and other experts say. “One of the main criticisms of this diet is that many people tend to eat too much protein and poor-quality fats from processed foods, with very few fruits and vegetables,” according to the Harvard Health Blog. In various studies, keto diets have been singled out for having serious shortcomings and even being dangerous.

Intermittent fasting, meanwhile, may not work in the long run and comes with notable risks, multiple studies have shown. The idea is to restrict food intake to certain hours during the day or even to skip eating on certain days.

The latest research to question the safety of intermittent fasting compared US adults who restrict their daily eating window to an 8-hour period with those who take a more standard approach of eating across 12 to 16 hours during the day, based on self-reported data. The time-restricted eaters were found to have a 91% higher risk of death by cardiovascular disease. The study, drawing from data on 20,000 people, is being presented this week at a meeting of the American Heart Association, but the research has not been published yet in a peer-reviewed journal and is considered preliminary. As with most diet and nutrition research, the study does not prove cause and effect, and follow-up studies are needed. In fact, it was criticized for being inconclusive the moment it was publically announced.

What should you believe?

Confused? Join the crowd. If we know anything about nutrition research, it’s that we should not rely on any single scientific study to guide our diet decisions.

“When certain diets show promising findings in research, many well‑meaning, non‑nutrition clinicians will be quick to recommend these approaches,” Patterson says.

Another problem with most diets: Even if they show promise, people rarely follow them in the way they’ve been researched.

As Patterson puts it: “A common practice is that people will apply certain features of a diet, instead of the actual dietary pattern that was researched. Without proper guidance, people may end up practicing unhealthy behaviors that put their health at risk.”

As you navigate the online world of diet advice, here are several red flags to watch for.

• Restrictive diets, unless recommended by a physician or dietician who is familiar with your entire health profile. Every restrictive diet comes with risks, in some cases for some people, other times for most or all people.
• Influencers who create slick websites and big bandwagons by claiming their scheme is science-backed. You can’t know the extent to which they cherrypick findings and cite dubious studies, or fail to point out the potential risks of their diet plan.
• Payment required. Be wary of any diet scheme that requires you to pay for the plan, the app or the powder or potion. While for-profit schemes are not all disingenuous, it’s easy to be hoodwinked by diet hucksters and even well-meaning health advocates whose primary motive is profit.
• Your best friend swears by it. Unless your best friend is a nutritionist and has studied your health profile, just nod politely (and forward this article to them).

Finally, apply the smell test to diet and nutrition advice before you consume a single morsel of the marketing hype. If it sounds too good to be true, it almost surely is.

The 80/20 rule

If you have a medical condition that requires choosing or avoiding certain foods, discuss the right approach with a nutritionist, a dietician, or a knowledgeable physician, who can properly evaluate your health and your specific needs.

If try diets for other reasons — like because some interwebs influencer has convinced you to eat nothing but pig livers or dandelions—consider taking a page from Patterson’s book.

Despite the bewildering array of fad diets and all the uncertainties, certain elements common to many popular diets can be fruitful for most people, she notes: controlling portions, eating more plant-based foods; and avoiding sugar and ultraprocessed foods.

And then eat thoughtfully, and don’t be too hard on yourself.

Patterson suggests an 80/20 rule, in which you seek not dietary perfection but a healthy, sustainable, balanced approach to eating. Follow healthy eating patterns 80% of the time, and don’t worry about the other 20%.

“One of the most important experiences that a dietitian can share is that perfection is not only unattainable but also unnecessary,” she says. “Even centenarians often admit to some lifelong indulgences. A healthy diet does not have to be all-or-nothing. The occasional treat is not harmful.”

Your support makes my reporting and writing possible. To make your days better, check out my book: Make Sleep Your Superpower. And if you’re a writer, see my Writer’s Guide newsletter.