Is fruit bad for you? Yes and no


In her weekly Ask the Nutritionist column, Nonie De Long tackles the contentious issue of including fruit in your diet

Dear Nutritionist, I am writing to ask about fruit. I’ve read a lot about a keto diet and I want to use it in the new year but I don’t want to give up fruit. Keto doesn’t seem possible with fruit. Is fruit actually bad for me? —John

Dear John,

Fruit is a contentious issue at present in nutrition circles. I find where people fall on the issue tends to reflect their own preferences. But we need to be wary of that. It’s important to understand the issue to make a decision in keeping with our goals, food preferences, and our particular health obstacles to create a personalized diet plan that will best serve us. This is why I suggest those who are struggling see a professional at least once for dietary recommendations. There are a lot of things to consider.

Regarding fruit, we have been indoctrinated by government food policy to believe that fruit and veggies are healthy and benign. They are the nutritional gold standard, and everything else is optional. Indeed, other whole foods like meat — and especially offal — have been maligned in the media in recent years to be dirty. This is not unlike the dominant view on sex in the Victorian era.

But we need to get past such associations and make food choices based on science. And by science I don’t mean some statement by white coats in a lab somewhere extracting the RNA of bananas to inject into other animals for the purpose of packaging banana RNA as the new blockbuster product. And I’m not talking about large studies relying on people with various health conditions lumped together reporting what they ate and didn’t eat — in a completely uncontrolled environment. I’m talking about the science of life.

How do you feel when you eat that food? What is the impact on your body and health? This is the ultimate analysis of foods and their nutritive value for each specific person. For this reason, when you’re experimenting with diet I wholeheartedly recommend keeping a food journal and every day noting what you ate and how you feel in your body, mood, and mind. How is your elimination? How is your sleep? These are all impacted dramatically by even small changes in diet.

So keeping a journal can help figure out if something works for you or doesn’t. And it only takes about 10 minutes a day, and trains us to start to think about these things and to listen to our bodies. But for this experiment, like any good scientist, we must follow through! If we want to see how removing a food makes us feel, we must give it enough time to stop craving that food.

This applies to any restriction we might want to study. Ditto any addition. To study how one food makes us feel we want to not add another new food in while we’re doing this experiment. Changing one food at a time helps us see clearly what the impact of that food or food group is. We can use macro tracking apps to help us log our foods and see the results. These help us correlate not only the foods but the food groups and macros to health outcomes.

Now to get into the issue of fruit specifically. The idea that it’s healthy is problematic on a few levels. We tend to think anything that contains fruit is healthy or sweetened with fruit instead of sugar, is healthy. This isn’t true. Neuroendocrinologist Robert Lustig, has done a tremendous job of studying fructose (the fruit from sugar) and its impact on health and has declared that it is equal or worse than sucrose in terms of our health. So is fruit bad then?

Well, that depends. This is where diets must be personalized. Fruit is full of fibre and vitamins and minerals, which we all need for optimal health. And some fruits have incredible amounts of antioxidants — some berries in particular like acai or blueberries. Antioxidants are anti-aging, so that’s good news. And fruit can be satisfying because of the pleasant, sweet flavour. But modern fruit is very sweet. We have changed our fruit over time to be bigger and sweeter than it was naturally.

Even though fruit sugar is natural, it still spikes insulin and blood sugar. This was the issue Dr. Lustig studied. For example, raisins contain up to 72 per cent sugars by weight. One mango has about 45g of sugar. A cup of grapes has about 23g of sugar. A medium just-ripe banana has about 14g of sugar and this increases as the banana ripens. But a ripe avocado only has about 1.33g of sugar. So not all fruit is equal either! We can see though, that eating several servings of sweet fruit a day can have a serious, undesirable impact on blood sugar.

On the other hand, for clients with digestive woes and leaky gut or serious autoimmune issues, fruit can be nutritive and often well tolerated and can replace dessert with a healthier option. This is because most fruits require very little digestive energy and don’t require the same enzymes in the intestine to break them down. They also don’t have the anti-nutrients veggies have. So if the intestinal lining is compromised, fruit still gets digested and absorbed. And they are far superior to baked goods in terms of their nutrient density.

For active children who need a quick snack, whole, fresh fruit is far superior to processed or packaged snack foods. For athletes who need to get or keep their carbohydrates up for energy stores and performance, whole, fresh fruit is superior to many processed pre-workout products. In these cases fruit can be very healthy. But anyone with blood sugar issues needs to really monitor fruit intake. Ditto anyone trying to do a keto or very low carb diet. And those trying to lose weight. Let me explain.

The primary concern I see in clients today is blood sugar dysregulation and insulin resistance, usually (but not always diagnosed) as diabetes or pre-diabetes. And this is a recipe for chronic health deterioration and disease risk, even when “managed” by medications. The optimal diet to control and even reverse type II diabetes and the underlying blood sugar issues is a very low carb, whole foods, omnivore or carnivore diet. In essence, a whole foods keto diet. And on this diet, most fruit is a deal breaker. The exception is low glycemic berries.

This is exacerbated when fruit is made into a juice or dried. Or when it’s used to sweeten other products. In all of these cases, the fruit sugar is condensed and/ or separated from the fibre and/ or water. This makes the product sweeter by volume, and much higher glycemic.

The glycemic load or index are measuring tools to discern the impact foods have on our blood sugar. Have you ever felt like reaching for a sweet or fruit and enjoyed it only to find your energy completely sapped within an hour? This is a key symptom that you may be suffering from pre-diabetes, otherwise known as insulin resistance.

It’s a dilemma because it sets you up for stronger food cravings that never satisfy. That’s because the food energy is being quickly stored away rather than used to give you energy due to your body overreacting to sugars. This happens when we’ve eaten way too much sugar for too long. This can include all carbohydrates, which inevitably are converted into sugars in the body. So you can see with this scenario, sweet fruit or fruit juice can trigger the same response that a Mars bar triggers. Your body doesn’t know the difference!

If you’re unsure if you struggle with blood sugar issues there is a simple test. It only requires a measuring tape. You want to measure around your belly button area and write the number down. Now measure the widest part of your hips. If the measurement of your belly is higher than that of your hips, you are in the danger zone and should get your blood sugar tested. You should also consider these tips when you want to consume fruit.

When consuming fruit in the case where a person struggles with blood sugar issues, it’s important that fruit follow a meal. This is helpful when we want a sweet after a meal and are having a hard time getting over that. A cup of whole fruit can help us move toward less sweets. Or you can try a cup of fruity herbal tea that is unsweetened. But stay away from dried fruit, processed fruit snacks, and fruit juices. Even “healthy” fresh smoothies made with a lot of fruit can spike blood sugar. And these ultimately set us up for diabetes.

Eating fruit after a meal or in the presence of proteins and fat ensures it will not be digested too quickly, which means it will not spike your blood sugar. If you want to add a little to a smoothie, keep it to a cup and make sure there is ample protein in the smoothie. Fibre, fat, and protein slow the absorption of sugar and help us avoid blood sugar spikes that drive insulin resistance. It’s also a good idea to learn which fruits are higher and lower in sugar and stick to the lower ones except as a treat.

Thank you for writing in, John. I hope you find this helpful as you embark on your keto journey.

If readers have their own questions they can email me at You can also find me online at Have a lovely week!


Nonie De Long


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