Understanding the 150ml Limit: Why is 150ml of fruit juice and smoothies the maximum recommended per day?

December 13, 2025 •

3 min read

Official guidelines, such as those from the NHS, advise limiting your daily intake of fruit juice and smoothies to a combined total of no more than 150ml. This seemingly small amount is based on significant nutritional differences between whole fruit and its liquid form.

Quick Summary

A daily 150ml limit for fruit juice and smoothies exists because juicing releases free sugars that increase health risks like tooth decay, weight gain, and blood sugar spikes, while removing much of the fruit's beneficial fibre.

Key Points

Free Sugar Release: Juicing breaks down fruit cell walls, releasing natural sugars that behave like 'free sugars' and are rapidly absorbed by the body.
Risk to Dental Health: The combination of free sugars and natural acids in juice significantly increases the risk of tooth decay and enamel erosion.
Crucial Fibre is Lost: The juicing process removes most of the beneficial dietary fibre found in whole fruit, impacting gut health and satiety.
High Calorie and Poor Satiety: Juice is calorie-dense and its liquid form means it is less filling than solid fruit, leading to easier overconsumption and potential weight gain.
Blood Sugar Impact: Rapid absorption of free sugars from juice can cause sudden spikes in blood sugar levels, contributing to health risks over time.
Moderation over Volume: The 150ml limit ensures a balance, allowing for some nutrient intake from juice without the negative effects of excessive sugar consumption.

The Core Nutritional Issue: Free Sugars

When whole fruit is eaten, the natural sugars are contained within the plant's cell walls, and the fibre slows their release during digestion. However, juicing breaks down these cell walls, freeing the sugars. These become 'free sugars,' rapidly absorbed by the body, similar to added sugars in other sweet drinks. A single glass can contain the sugar equivalent of several pieces of fruit.

The Impact of Free Sugars on Health

Rapid absorption of free sugars causes quick spikes in blood sugar and insulin. High consumption is linked to increased risks of obesity and type 2 diabetes. The ease of drinking large quantities means a high sugar load can be consumed quickly, unlike eating whole fruit which requires more effort and time.

The Problem for Dental Health

Fruit juice's concentrated free sugars and natural acidity are detrimental to dental health. Bacteria in the mouth feed on these sugars, producing acids that erode tooth enamel, potentially leading to decay. Sipping juice frequently prolongs this exposure. To mitigate risk, guidelines recommend consuming fruit juice and smoothies only during mealtimes.

The Critical Role of Fibre

Juicing significantly reduces or removes the fruit's dietary fibre, as the pulp is often discarded. While smoothies retain more fibre, blending still alters it. Fibre is vital for digestive health, blood sugar control, and promoting fullness, which can help manage calorie intake. Without fibre, juice and smoothies are less satiating than whole fruit, potentially leading to higher overall calorie consumption.

Calorie Density and Weight Gain

Due to their high sugar content, fruit juices are calorie-dense beverages. Liquid calories are generally less effective at providing a feeling of fullness compared to solid foods. It's easy to drink a large amount of juice, consuming many calories without feeling satisfied, whereas eating the equivalent amount of whole fruit is more filling.

Comparison: Whole Fruit vs. Juice


Feature	Whole Orange	150ml Orange Juice
Dietary Fibre	High, intact fibre slows digestion.	Low or absent, as pulp is removed.
Sugar Absorption	Gradual absorption due to fibre.	Rapid absorption of 'free sugars'.
Satiety	Highly satiating due to fibre and chewing.	Poorly satiating; liquid calories are less filling.
Dental Impact	Lower risk of decay; less concentrated sugar and acidity exposure.	Increased risk of decay and erosion from sugar and acid.
Nutrient Density	Good source of fibre, vitamins, and minerals.	Good source of some vitamins (e.g., Vitamin C) but lacks fibre.

A Balanced Approach to Enjoying Juice and Smoothies

The 150ml limit allows for some vitamin and mineral intake without the negative effects of excessive sugar. To make the most of this portion:

Dilute with water: Reduces sugar concentration per sip.
Consume with meals: Helps protect teeth and slows sugar absorption.
Prioritise homemade smoothies: Including whole fruit retains more fibre.
Add other ingredients: Boost smoothies with protein/fats (yogurt, nuts) for better satiety.
Focus on whole fruit: Whole fruits and vegetables with intact fibre should be the main source of your '5-a-day'.

For further guidance, consult resources like The Eatwell Guide.

Conclusion

The 150ml limit on fruit juice and smoothies is public health advice balancing nutrient intake with risks. While they offer some vitamins, the high free sugar content, lack of fibre, and potential for overconsumption contribute to dental problems, weight gain, and blood sugar issues. Whole fruits remain the best option, and juice should be consumed sparingly as part of a balanced diet.

Frequently Asked Questions

The process of juicing or blending fruit breaks down its cellular structure. This releases the naturally occurring sugars, known as 'free sugars', which are absorbed by the body much faster than the sugars in whole fruit.

Yes, the limit applies regardless of whether the juice is fresh or from concentrate. The key issue is the release of free sugars, which occurs whenever fruit is crushed or blended.

No, official guidelines state that fruit juice and smoothies can only ever contribute a maximum of one portion of your 5-a-day, regardless of how much you drink.

A homemade smoothie that includes the whole fruit (including skins and pulp) does retain more fibre than juice. However, it still contains free sugars due to blending and should be consumed in moderation.

Dietary fibre, lost during the juicing process, is crucial for digestive health. It also slows down sugar absorption, helps regulate blood sugar, and promotes feelings of fullness, which is vital for managing calorie intake.

Yes, diluting juice with water can reduce its sugar concentration and acidity, making a small amount go further. It's a good practice, but the drink still contains free sugars.

It is best to drink fruit juice and smoothies with meals. This practice helps to reduce the risk of tooth decay, as consuming other foods alongside helps to protect your teeth.