Skip to main content
food for thought

We’re bombarded with diet and nutrition advice. It comes from friends and family, social media, blogs, news reports, magazines, fitness trainers, health professionals and other sources.

With everyone acting like a nutrition expert, information that’s incorrect, misleading and without scientific backing is bound to arise – and stick around.

Here are five persistent nutrition myths and what you should know about them:

1. Avoid fruit because it’s loaded with sugar

It’s been said that eating fruit will prevent you from losing weight or, worse, make you gain weight. Or that you can’t eat fruit if you have diabetes.

Fruit gets an unfair bad rap for its sugar content. That’s especially true for bananas, even though one medium banana contains only slightly more sugar than a similar-sized apple or pear.

Whole fruit contains naturally-occurring sugar along with vitamins, minerals, phytochemicals and fibre, which slows down the absorption of sugar into the bloodstream.

A 2021 study found that, compared to eating little or no fruit, a higher fruit intake protected against type 2 diabetes (bananas included!). And, if you have diabetes, research suggests that including fruit in your diet can help improve blood glucose control.

It’s true that some people may need to limit their fruit intake. Still, whole fruit doesn’t need to be avoided. I’m sure many of us could stand to eat more fruit.

2. Eat protein right after a workout

To optimize muscle-building, you may have been told it’s necessary to consume protein within 30 minutes of finishing a strength workout.

Doing so within this “anabolic window” is said to allow your muscles to repair and recover more effectively than if you wait longer for your postworkout nutrition.

Yet a review of 43 randomized controlled trials, published in 2013, revealed that consuming protein within 60 minutes of a workout had little effect on building muscle. A strong predictor of muscle gain, however, was the ability to consume total daily protein requirements.

No time to grab a protein shake immediately after a training session? Don’t stress.

Be sure, though, to include adequate protein in your daily diet to support your fitness goals. And distribute that protein over three or four meals.

3. Soy increases breast cancer risk

This notion revolves around soy’s isoflavones, natural plant compounds that have a very weak estrogenic effect.

A woman’s risk of breast cancer is related to the estrogen made by her ovaries.

Soy isoflavones are structurally distinct from human estrogen. Once consumed, soy isoflavones do not affect the body’s natural estrogen.

No studies in people have found that soy consumption increases breast cancer risk. In fact, some studies suggest that soy may protect against breast cancer and breast cancer recurrence.

As part of a healthy diet, a moderate intake (one to two servings a day) of whole soy foods does not increase breast cancer risk. Traditional soy foods such as tofu, tempeh, edamame and soy milk are good sources of protein, fibre and other nutrients.

4. Dairy foods are inflammatory

Ongoing low-grade inflammation is associated with several chronic illnesses including heart disease, stroke, type 2 diabetes, cancer, inflammatory bowel disease and rheumatoid arthritis.

An eating pattern that’s high in refined carbohydrates, added sugars, red meat and saturated fats and low in fruits, vegetables, whole grains and omega-3 fats is considered inflammatory.

It’s common to hear that dairy (milk, yogurt, cheese) is inflammatory. Perhaps that’s because dairy contains saturated fat, which can increase inflammation.

But the evidence doesn’t support a link between dairy and inflammation. Some studies have tied dairy, especially fermented dairy (yogurt, aged cheese, kefir), to a lower risk of type 2 diabetes and cardiovascular disease.

A 2021 review of 27 randomized controlled trials found that dairy products had a neutral or beneficial effect on blood markers of inflammation in adults who didn’t have a severe inflammatory disorder. Studies suggest fermented dairy has weak anti-inflammatory effects.

Unless you have a milk allergy, there’s no reason your anti-inflammatory diet can’t include dairy. The Mediterranean, DASH and Nordic diets certainly do.

5. Eating nuts leads to weight gain

Eating a handful of nuts each day is thought to help guard against heart disease, type 2 diabetes and cancer. Nuts are also a key ingredient in a blood pressure and blood cholesterol-lowering diet.

Yet, many people avoid eating nuts for fear of gaining weight.

Nuts are high in calories owing to their heart-healthy unsaturated fats. There’s no evidence, though, that eating nuts on a regular basis leads to weight gain.

Instead, plenty of studies have found that consuming nuts is associated with less weight gain and a lower risk of overweight and obesity.

The protein, fibre and fat in nuts promotes satiety and reduces appetite. Nut eaters have been shown to consume fewer calories at later meals too.

And thanks to their fibrous cell wall, it’s thought our bodies don’t absorb 20 to 25 per cent of the calories in nuts.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD

Follow related authors and topics

Authors and topics you follow will be added to your personal news feed in Following.

Interact with The Globe