Protein chips, sex chocolate: what are ‘functional foods’, and do they actually boost health?

You’re at the grocery store, looking for a sweet snack. But these days, the chocolate aisle promises so much more than that: mental clarity, a stronger immune system, PMS relief and even sexual stamina – all in a few squares.

Chocolate is hardly the only treat to be reborn as a wellness product. Supermarket shelves now boast chips with added protein, gut-friendly sodas and collagen oatmeal – all part of the fast-growing “functional foods” market, which is expected to reach $586bn globally by 2030.

Functional foods have been around for decades, but are taking off anew. Consumers have become more health-conscious, weight-loss drugs are changing people’s eating habits and strained household budgets make non-essentials harder to justify, said Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University.

“That’s sort of a perfect storm,” Nestle said. “This is the era of wellness influencers – whether science has anything to do with it, we can argue about.”

So, can souped-up snacks actually change our brains and bodies, or is the explosion of functional foods just another wellness fad?

What are functional foods?

There is no regulatory definition for “functional foods”, and the term means different things to different people. But nutritionists generally agree that the term refers to foods that provide specific health benefits or enhance the body’s processes, beyond providing basic nutrition.

The category includes whole foods like blueberries, which contain vitamin C and fiber, as well as metabolites that, according to early research, may protect the brain as we age. Functional foods also include modified foods, like vitamin A-enriched rice, prebiotic-added yogurts or energy drinks.

We’ve entered a new age of functional foods in recent years, dominated by added protein and fiber as well as vitamins, probiotics, omega-3 fatty acids and minerals such as magnesium, according to the market research firm Lumina Intelligence.

Other ingredients are niche but on the rise, said Flora Zwolinski, an insight lead at Lumina who analyzes food and nutrition trends. They include nootropics, or compounds that may support cognitive function by boosting signals between neurons (eg, caffeine, lion’s mane mushrooms, L-theanine) and adaptogens, which are herbs used to help the body cope with stress (eg, ashwagandha, reishi).

“We’ve got the growth of these products that are claiming they can support quite specific health goals, whether it be energy, focus, immunity or overall health that’s much more well-rounded than just the old school weight loss or muscle gain,” Zwolinski said.

Is it worth adding modified functional foods to my diet?

Most functional food add-ons are nutrients we really do need. For example, protein is an essential macronutrient that allows our cells to grow and repair. Most people don’t get enough fiber, which is linked to a lower risk of heart disease, stroke, type 2 diabetes and bowel cancer. And magnesium plays more than 300 roles in the body, helping with everything from blood sugar control to bone health.

However, nutritionists say the extra nutrients or probiotics added to functional foods may not be enough to actually boost our diets or health. And when it comes to trendy additives like lion’s mane or collagen, the doses are often far below what has been studied in clinical trials.

According to a 2019 book about functional food regulations, fewer than 0.1% of dietary supplements or functional foods were found effective in placebo-controlled, randomized studies. A Japanese analysis in 2024 found that most functional food trials either did not publish their results or selectively reported their findings in their favor.

“There’s quite astonishingly little evidence” behind functional food claims, Nestle said. “It has nothing to do with science. It’s about marketing.”

When it comes to heavily processed functional foods, “they’re not the biggest bang for your buck” when it comes to nutrition, said Grace Derocha, a nutritionist who is also a spokesperson for the Academy of Nutrition and Dietetics.

If you’re considering adding them to your diet, note that not all functional foods are created equal. Derocha says we’re better off with un- or minimally processed options, like oatmeal or kombucha, because our bodies absorb the nutrients from them more effectively.

What are the rules for making functional food claims?

In the US, the Food and Drug Administration has three categories for food and supplement claims.

The first is health claims, which link a nutrient and a disease (“calcium reduces the risk of osteoporosis”). The second is nutrient content claims, which specify how much of a nutrient is found in that food (“milk is high in calcium”). The third is structure or function claims, which describe how a nutrient affects the body (“calcium builds stronger bones”).

Each category comes with different rules.

A company can make function claims without FDA pre-approval as long as they are not false or misleading.

By contrast, companies must ask the FDA before they make health claims and must meet certain criteria to make nutrient content claims. For example, to say a food is “an excellent source” of a nutrient, vitamin or mineral, it must contain at least 20% of the daily recommended amount.

Food companies can also make functional claims even if their products are otherwise unhealthy – for example, if they contain added protein but also have high levels of salt, saturated fat or cholesterol. But in those cases, health claims are not allowed, and nutrient content claims must feature disclaimers, which is why food manufacturers often opt for functional claims instead.

In the UK, there are different categories and rules around food claims. Certain nutrition claims are allowed (eg, “low-fat” is allowed if the product has a 30% fat reduction compared with similar offerings), as are pre-approved, evidence-backed health claims (“Iron contributes to normal cognitive function”). But food labels cannot say an item prevents, treats or cures a medical condition, or promise weight loss.

What happens if a food company makes a misleading health or functional claim?

It’s possible for a food company to make an inflated claim that is not contested, but in some cases, the FDA or the US Federal Trade Commission can decide to crack down.

For example, when it comes to health claims, in 2010, the FTC forced Dannon to drop what it said were “exaggerated” claims about its yoghurt and a dairy drink being scientifically proven to relieve intestinal irregularity and prevent colds and the flu – the FTC said Dannon didn’t have the evidence to back these claims.

Functional claims, which are less specific than health claims, are murkier territory in the US. Supplement makers have to report their functional claims to the FDA, but food companies don’t. The agency also isn’t clear on what would count as false or misleading claims, meaning food companies are free to make plausible, vague promises on their packaging with little oversight.

In the UK, almost all nutrition and health claims must be approved.

How should I make sense of functional food claims?

Take these claims with a grain of salt. The ingredient list and nutrition label will give you more information about whether that turbo-charged soda, cracker or coffee creamer suits your health goals, or if it’s best enjoyed for what it is.

Derocha, the nutritionist, said that for most people, something like a high-protein granola bar would be harmless, as long as they had a well-rounded diet overall and get protein in other ways, too.

“Just be aware of what you’re actually putting into your body, because not all products that are labeled ‘functional’ are truly effective,” Derocha said.

• Gabriela Galvin is a freelance journalist in London who covers health and social policy