Food trends often come and go, and with them a lot of confusion about what we should and shouldn’t eat for a healthy, balanced diet.

Nutritional epidemiologist Karin Michels, professor and chair of the epidemiology department in the UCLA Fielding School of Public Health, USA, gives her views on the latest diet crazes, and whether one should try the popular Paleo diet, cut out carbs, add in fat, and even have that morning cup of coffee.

Myth: Cut the carbs

Low-carb diets have seen a surge in popularity in recent years, however instead of cutting carbs out of your diet Michels advises you replace refined carbohydrates and sugars with whole grain carbs such as quinoa, oats, rice and pasta. She also adds that there is no good reason to avoid gluten unless you’re intolerant, and by avoiding gluten you will also miss out on important nutrients and fibre that come from grain.

Myth: A low-fat diet is best

Fat has long been seen as the enemy to a healthy diet, with many believing that a low-fat diet is good for the heart. However Michels disagrees. Instead she says most people need to change the type of fat in the diet, avoiding saturated and trans fats and adding in unsaturated fats. Unsaturated fats found in olive and canola oils and fish, nuts and avocados raise the body’s HDL (”good”) cholesterol, while saturated fats from animal and dairy products and the artificial trans fats found in margarines and cookies will raise the LDL (”bad”) cholesterol.

In line with recent reports she also cautions against coconut oil, which although was once assumed to be healthy, is full of saturated fat.

Myth: We should eat like our ancestors

Although the popular Paleo diet advocates following the diet of our hunter-gatherer ancestors – eating lots of energy-dense red meats and excluding grains – Michels points out, “We are nothing like our ancestors – instead of running around all day, most of us sit in front of our computers.”

She says the best approach is a balanced diet that limits or avoids red and processed meats, which were classified as carcinogens in 2015 by the World Health Organization’s International Agency for Research on Cancer.

Myth: A well-balanced diet provides all essential nutrients

Michels says she is frequently asked about whether supplements are worth it, and says that the only one she strongly recommends is vitamin D. “Two-thirds of the US population – especially those living in colder climates – is vitamin D-deficient, and many don’t realise it,” she says.

The best source of vitamin is the sun, but using sunscreen to block out the sun’s harmful rays also blocks vitamin D production in the body. Another source of the nutrient is from food, but as it’s nearly impossible to get enough from the diet. Michels says the easiest way to top up levels is through supplements.

Myth: Coffee is unhealthy

A cup of joe used to have a bad reputation when it came to health, but Michels is in agreement with recent research, saying coffee can help lower the risk of many common diseases, including diabetes, colorectal cancer and aggressive prostate cancer subtypes.