Why Fruit Juices Are Not Healthy

The phrase “100% natural” on a box of orange or apple juice sounds reassuring, but the very process of turning a fruit into a clear beverage changes everything: fiber disappears, while sugars remain in free form. As a result, the product traditionally considered “healthy” is actually closer to a dessert than to a thirst-quenching drink.

Below, we explain in detail how the fruit changes when juiced, what happens to the sugars in the body, and why even freshly squeezed juice should be considered a treat rather than a staple beverage.

From tree to carton: where does the “freshness” go

After juicing, commercial juice is stored for months in massive anaerobic tanks: oxygen is removed from the liquid to slow down oxidation and extend shelf life up to a year. Along with the oxygen, volatile aromatic compounds also disappear, so before bottling, manufacturers add so-called “flavor packs” — blends of essential oils and essences collected and recombined by aroma companies. The label doesn’t mention this, because the source is still considered the same orange or apple, just “re-aromatized.”

Freshly squeezed juice undergoes less processing and therefore retains more unstable vitamins, but it still lacks fiber: microscopic filters separate the pulp, leaving behind an almost pure sugar solution.

Fiber vs. free sugars: how metabolism changes

In whole fruit, sugars are “locked” inside cell walls. While we chew and then digest the fibers, glucose and fructose are released slowly, giving the liver time to process them. In a glass of juice, the same sugars are already dissolved; within minutes, they enter the bloodstream, then the liver, and if the dose exceeds the body’s needs, the excess fructose is converted into fat.

Systematic reviews confirm: a regular daily serving of 100% juice in children is associated with a gradual increase in body mass index, and in adults, weight gain is observed if excess calories are not accounted for. In other words, small amounts of juice are unlikely to cause problems in healthy, active individuals of normal weight, but may pose a significant risk for those who are overweight, have metabolic issues, or lead a sedentary lifestyle.

The more sugar, the more calories

Sugary drinks in general, and fruit juices in particular, are among the most calorie-dense foods. They contribute to weight gain, and when we drink juice with meals, we consume significantly more total calories.

The traditional argument “juice contains natural sugar, while cola contains added sugar” does not change the amount of free sugars. In 12 ounces (about 350 ml) of apple juice, there are about 36 g of sugar, while the same amount of cola contains 39 g — the difference is minimal.

The World Health Organization reminds us: it is advisable to keep free sugar intake below 10% of daily energy, and ideally around 5% (approximately 25 g for an adult). A single glass of juice already exceeds this “ideal.”

What are the risks of too much juice in the diet?

Observational studies show: two or more servings of juice per day increase the risk of hemorrhagic stroke by nearly 40% compared to moderate or rare consumption.

Meta-analyses in the field of type 2 diabetes reach a similar conclusion: sugary drinks, including fruit juices, are associated with higher incidence rates, while whole fruits are correctly associated with lower risk.

Controlled laboratory experiments complete the picture: the rapid spike in blood sugar after juice intake leads to increased insulin production and, with regular repetition, to insulin resistance and accumulation of visceral fat.

Is there any benefit to a glass of juice?

Vitamin C, folic acid, potassium, and a number of antioxidants are indeed present in juice. Freshly squeezed orange juice, for example, remains a convenient way to meet the need for ascorbic acid when fresh fruit is scarce.

However, in terms of overall nutritional value and satiety, juice inevitably loses to a whole orange: after drinking the equivalent of two or three fruits in liquid form, there is almost no sense of fullness, whereas eating the same amount of whole fruit is quite difficult.

With moderate physical activity, an occasional serving of up to 150 ml of juice generally does not cause harm, but regular consumption of larger amounts becomes a risk factor. This is especially true for children, people with prediabetes, non-alcoholic fatty liver disease, and excess weight, all of whom already have impaired glucose tolerance.

Fun facts

• The first commercial juice was released by American Thomas Welch in 1869 by pasteurizing non-fermented grape juice.
• The average adult European drinks about 20 L of juice per year — equivalent to > 4 kg of sugar.
• Glass bottles can be recycled infinitely, whereas multilayer Tetra Paks require complex sorting. Your packaging choice affects not only your health but also the drink’s climate footprint.
• 150 ml of orange juice contains as much free sugar as ~4 small mandarins, but eight times less fiber.
• In Brazil, the law allows the term “suco” only for 100% juice; everything else must be labeled “néctar.”
• Japan sells “30% vegetable & fruit juice” — marketing with nearly as much sugar as cola.
• Since 2011, a European directive has required that products labeled “fruit juice” must not contain added sugars or sweeteners; otherwise, they must be labeled “nectar.”
• One region controls the global orange tap: Brazil supplies up to 75% of all orange juice; drought or citrus greening in São Paulo state drives up prices worldwide.
• Vitamin C “evaporates” at 2% per day. An opened bottle of orange juice in the fridge loses ~12% of ascorbic acid in a week; after two weeks, only two-thirds remain.
• Orange is the world favorite. Despite competition from smoothies and “functional” drinks, orange remains the most popular juice on the planet and the top flavor in 23 major national markets.

Practical tips

1. Treat juice as food, not a drink. Drink water or unsweetened tea to quench thirst.
2. Choose a small glass. 100 ml of orange juice = ± 2 oranges worth of sugar.
3. Drink juice with meals. This reduces the risk of cavities and glucose spikes.
4. Dilute juice 1:1 with water or sparkling water — reduce sugar and keep the taste — you’ll get a natural “schorle.”
5. Choose juice with pulp: still low in fiber, but slightly more than in fully clarified products.
6. Read the ingredients. Words like “nectar,” “drink,” “cocktail,” or “juice-containing” signal added sugars.
7. Check the label: look for “100% juice” without “apple concentrate, glucose-fructose syrup.”
8. Save juice for special occasions. One serving — no more than 150 ml once or twice a week.
9. Use juice as an ingredient: marinades, dressings, smoothies with spinach or carrots — this way, you bring back some fiber.
10. Children under one don’t need juice at all. Breast milk, formula, and purées — yes; juice — no.
11. Offer children water or unsweetened tea; juice only as part of a meal, not as a grab-and-go drink.
12. Prioritize whole fruits. Healthy eating guidelines recommend at least two fruits and three vegetables per day.

What to do at home

The best response to thirst is still plain water: it contains no calories, doesn’t interfere with blood sugar balance, and helps avoid unnecessary energy intake.

It’s wiser to eat fruits whole — that way, the body receives fiber, vitamins, and a slow, liver-friendly sugar flow.

If you crave juice, make it yourself, leave some pulp, and limit yourself to a small glass at breakfast or with a meal — not between meals. For flavor, dilute it one-to-one with water — sugar content is almost halved while aroma remains.

Offer juice to children as a dessert, not a daily drink. Incidentally, that was the original idea behind commercial juice production: the first pasteurized grape juice, created by pharmacist Thomas Welch in 1869, was sold in church stores as a non-alcoholic alternative to wine — a treat for special occasions, not a daily hydration source.

Fruit juice is a concentrated solution of free sugars with some vitamins but no protective fiber. When consumed occasionally and in moderation, it can be a tasty addition to the diet, but as a primary drink, it leads to excess calories and increased metabolic risks. If you want to protect your liver, heart, and pancreas, reach for the fruit — not the glass. Eating fruit is always better than drinking it.