New Year, new you? With Christmas firmly in the rear-view mirror, the annual dieting frenzy is about to begin. Whether you’re looking to lose some weight, put some muscle on, or just improve your health, the likelihood that you’re thinking of going on a diet right now is higher than it has been at any point over the last 12 months.

Google searches for “losing weight” spike in January each year.

Trying to make better food choices can be confusing. Anyone who’s taken a glance at the health pages of a tabloid women’s magazine or their batty aunt’s Facebook page will know that nutrition science is deeply contested. Drinking red wine will increase your risk of cancer—but it will also reduce your risk of cancer. Coffee will prevent liver cancer—but drinking it too hot will give you oesophageal cancer. Even when the evidence isn’t contradictory, it’s often inconclusive. Does “calories in, calories out” help us understand how to lose weight, or is it a dangerous oversimplification? The only real consensus is that eating plenty of vegetables is probably a good thing. (But even then, articles like this one suggest that even veggies aren’t an unalloyed good.)

With science being an unreliable or incomplete source of accurate information, we turn to the next best thing: the internet.

Searching for diet advice on Instagram has become the nutritional equivalent of self-diagnosing your medical ailments through Google. You might be scanning for healthy-eating Instas to follow and considering the diets they promote. You might be looking for “fitspiration” from fitness coaches and people who’ve lost enormous quantities of weight or have turned their abs into rippling mounds of muscle. You might be considering joining up for Kayla’s #BBG program or Anna Victoria’s #FBG workouts.

While some of these accounts promote healthy lifestyles, a lot of what’s out there is produced by people who are being paid to shill the products they claim produce miraculous results. For example, the Fit Tea or SkinnyMe Tea you’ve seen multiple celebs boast about in their ‘grams is really just a diuretic, or the juice cleanses that claim to “reset your body” and “leave you with a feeling of purity and revitalization.” Insta celebs are paid figures in the tens of thousands to plug these products, with some receiving sums up to $250,000 for promoting laxative teas. You only get so many shots at making a change, and the misinformation that you see in your feed may be more likely to lead you into months of yo-yo dieting than to lasting, sustainable changes.

So if you want to get fit this year, take a break from salivating over delicious Insta recipes and lusting after the hard bodies of those who make them. Instead, swing to the other end of the internet’s rabbit hole: Reddit.

Reddit’s no-nonsense diet tips

If you’re serious about finding out what works and making real changes, there is not a community more sceptical and scrupulous than Reddit. Known to outsiders mostly as the domain of internet trolls and Pepe memes, they also have a quiet, reliable, and incredibly active health community. There are whole corners filled not only with recipes for delicious, healthy food, but also with people devoted to questioning the evidentiary basis for the diets they’re following—and actively working to understand what works and why. Reddit is famous for this kind of culture, where individual users tend to be suspicious of mainstream norms and beliefs, and curious about what little-known facts might be out there.

Many of them treat their bodies as “n of 1” experiments, meaning they self-trial themselves as a single case study, using diaries, spreadsheets, or informal experimentation to figure out what works for them. The sum total of what they find can be helpful not just for understanding how to tinker with what works for you, but also for producing general guidelines on what works and what doesn’t overall. Some of the most popular subreddits to sift through to start are r/paleo, r/whole30, r/keto, r/loseit, r/gainit, and r/nutrition.

For the last two and a half years, I’ve been studying the social dynamics of internet fitness and nutrition communities (especially the paleo crowd) for my PhD. I’ve found that the people who are the most successful at achieving their goals are the ones who question the facts we’re fed—and there’s no better place for that than Reddit.

But it’s the way Reddit’s diet community comes to their conclusions that makes them so reliable. When it comes to nutrition, there is no settled science. The “evidence” that studies produce can’t conclusively point you in any particular direction, because it’s always dependent on an array of factors that are often influenced by your genetics (and no amount of carb-cutting can change that). You could spend hours reading PubMed article abstracts and it would ultimately have the same result as mindlessly flicking through images of dramatic weight losses on Instagram. That means that what you decide to believe is really determined by who you decide to believe. Everyone’s got an idea of the secret to losing weight—you just have to choose whose to trust.

This is how Reddit collectively decides the best ways to lose weight or gain muscle—and I believe that this kind of method is as close to the ideal as you’re going to get in such a contested field.

So, how does Reddit decide who to believe? I’ve collated the different ways in which people decide that someone knows what they’re talking about—and that they’re not just in it for the money. What follows are a set of characteristics and behaviors I call “signifiers of expertise.” They’re not diet tips. Instead, they’re tactics to help you form a strategy to determine whether the people harping those theories are trustworthy. Using examples from the paleo subreddit, r/paleo, we can all learn how to better interrogate the diet tips we see proselytized around us.

They’re willing to change their mind

The hundreds of threads and thousands of comments I’ve examined suggest that the people who are trusted the most are those who are willing to admit when they’re wrong. They will sacrifice their dogmatic adherence to “the rules” when they can see that the evidence is going against their current position. To quote one of my interviewees, “I like hearing people say that nothing works for everyone and that everyone is different. If someone uses any absolutes when talking about health, they’re more than likely pushing an agenda or selling something. I also trust people, like Robb Wolf, who have changed their opinion on things. As you learn, your stance changes.”

… but not too easily

If you’re willing to drop all your ideas, arguments, and evidence at the slightest provocation, it’s unlikely that you’re going to be seen as someone who’s thought everything through thoroughly—and therefore as someone who can be trusted to give advice.

They don’t have anything to sell

Commercial success doesn’t always correspond with truthfulness. Some of the most popular gurus in diet communities are those who aren’t constantly trying to sell supplements in every blog post. But be careful: If someone tells you they’ve got nothing to sell you, that’s a marketing tactic, too. They might not want your wallet—but they likely want your ad revenue.

… or if they’re selling something, they’re selling more than one thing

If someone insists that what they’re giving you is the only way to achieve the change you want, they’re almost certainly wrong. If what they’re selling you is the advice itself, and they recommend a broad range of products, it’s less likely that they’re taking you for a ride.

They have relevant credentials

Just because someone has “Dr” before their name doesn’t mean they know anything about nutrition. Look for people who have degrees and experience specifically in dietetics, nutrition, exercise science, and related fields. Surprisingly, medical doctors are often seen as poor sources of dietary advice because medical schools are slow to adapt to and teach new developments in nutrition.

Their funding doesn’t represent a vested interest

Whatever research you decide to pay credence to, it’s more-than-likely funded by someone. That might be by the state or a university, but it also might be a business or individual with vested interests in a particular outcome. For example, studies on pharmaceuticals that are funded by the company that produces the drug are far more likely to show a positive result, as any studies they conduct that produce negative results are unlikely to ever see the light of day. What unites almost all “unorthodox” diets—paleo, keto, Whole30, raw-vegan fruitarianism—is a distrust of the mainstream nutritional wisdom that often comes from these kinds of studies on account of who is funding them. You’ll find extensive critiques of a lot of dietary shibboleths with even a brief visit to any of these communities.

They give citations for their claims

Again, you need to be careful here. Often discussions devolve into a competition to see who can cite the most studies—and nobody’s got time to read all that. But if someone makes a claim and then they link to evidence to substantiate it, they’re probably better informed than the average user. That’s especially true if they engage with the substance of the article they’ve cited.

They look like they know what they’re talking about

When I started my PhD, I assumed that fitness communities operated on the principle of the literal “survival of the fittest”: that the people who were most likely to be believed were the most jacked. (I even titled my masters thesis “Do you even lift, bro?”) It’s true that people are more hesitant to take dietary advice from someone who looks like it hasn’t done them a huge amount of good, but you should be careful not to be entirely taken in by someone’s physique. Dave Asprey, creator of the “Bulletproof Diet,” puts his high performance down to butter in his coffee—but it more likely has to do with the smart drugs and testosterone replacement therapy he also uses. Likewise, the Atkins diet isn’t entirely undermined by the fact that Atkins himself died of a heart attack.

Other people tell you they’re trustworthy

Many of the people that I interviewed and the comments I analyzed suggest that friends, family, and community are the most important sources of trust. If someone I already trust implicitly tells me that something works, I’m far more likely to believe them than a stranger. Of course, this immediately comes up against a problem of regress: How do I know that I should believe the original person in the first place?

What they say vibes with your pre-existing, well-founded intuitions

The paleo diet—whereby people try to consume the kinds of foods that were present before the invention of mass agriculture—has been so successful in part because it taps into the well-established knowledge that evolution has shaped our species’ existence and molded us into what we are today. Diets that piggyback off of evolution therefore seem intuitive to us. That might lead you to feel more confident to go against the grain (as it were) and pick up a diet like paleo. But be wary: The same kind of “logical” explanations can be used to justify all kinds of conspiracy theories and odd beliefs, like grounding or the idea that sexism is just a matter of evolutionary psychology.

If you don’t fancy venturing into the depths of Reddit for your diet, nutrition, and exercise advice, understanding these signifiers will stand you in good stead wherever you get your information. Even if you do decide to scroll Instagram for inspiration, make sure you don’t just take claims at face value. Instead, interrogate each one to see if it’s coming from somebody worth believing. Be wary of nonsense masquerading as science and people promising changes that sound too good to be true—because they almost always are.