Sugary Drinks, Liquid Calories and Weight Gain: How Beverages Drive Obesity
- Katrin Peo
- Jun 9
- 10 min read
When most people think about sugar, they think about cakes, biscuits, chocolate, and sweets. However, one of the largest sources of sugar in modern diets often comes from something we drink.
Liquid calories from sugar-sweetened beverages, alcohol and sweetened drinks are one of the most overlooked contributors to excess energy intake. Unlike solid foods, they are consumed quickly and provide little satiety, making it easier to overconsume calories without noticing.
Soft drinks, energy drinks, sweetened coffees, flavoured waters, fruit juices, sports drinks, milkshakes, and many ready-to-drink beverages can contain surprisingly large amounts of sugar. Because these calories are consumed in liquid form, they may affect appetite and energy intake differently from calories eaten in whole foods.
Many nutrition researchers now consider sugar-sweetened beverages to be one of the major dietary contributors to obesity and metabolic disease worldwide.
Key takeaways from this article:
Liquid calories are poorly compensated for in the diet
Sugary drinks are a major driver of excess calorie intake
Alcohol contributes both sugar and calories
Diet drinks may reduce sugar intake but are not health foods
Water remains the best default beverage
What Names Can Added Sugar Hide Under?
When reading ingredient labels, sugar may appear under many different names apart from 'sugar'. Common examples include:
Sucrose (table sugar)
High-fructose corn syrup
Glucose syrup
Fructose
Fruit juice concentrates
Honey
Agave syrup
Even when sugar comes from a natural source, once it is removed from the food's original structure and consumed in liquid form, it can have similar effects on blood sugar and calorie intake as added sugars.
Why Liquid Calories Are Different
One reason sugary drinks are problematic is that our bodies do not register liquid calories in the same way they register calories from solid food.
A whole apple provides sugar, but it also contains fibre, water, and a structure that requires chewing. These factors contribute to fullness and help regulate appetite.
A glass of apple juice may contain a similar amount of sugar as several apples, but without the fibre that slows absorption and promotes satiety.
Research consistently shows that calories consumed in beverages are often poorly compensated for later in the day. In other words, people tend to drink calories without eating less food afterwards.
As a result, total daily calorie intake increases.
Common Sources of Liquid Sugar
Many people are surprised by how much sugar some beverages contain.
Examples include:
Soft drinks
Coca-Cola
Pepsi
Fanta
Sprite
Mountain Dew
A standard 330 ml can of soft drinks often contains around 32–34 grams of added sugar, which is 8 tsp of sugar.
Energy drinks
Red Bull
Monster Energy
Rockstar
A 250 ml can of Red Bull contains 27.5 g of sugar (which is about 7 teaspoons of sugar).
A 500 ml can of Monster Energy contains 55 g of sugar (which is about 14 teaspoons of sugar)
Sweetened ice teas
Lipton Ice Tea
Fuze Tea
Nestea Ice Tea
Arizona Iced Tea
For example 500ml Fuze Tea ja Nestea Ice Tea contain 22.5g sugar (which is 5.6t tsp of sugar).
Sweetened coffee beverages
Flavoured lattes
Frappuccinos
Ready-to-drink iced coffees
For example, a 220 ml Starbucks caramel ready-to-drink coffee contains 19 g of sugar (which is 4 teaspoons of sugar).
An 230 ml Ice Espresso coffee drink contains 20 g of sugar (which is 5 teaspoons of sugar).
Sports drinks
Gatorade
Powerade
Isostar
Sports drinks contain sugar and electrolytes and are intended for endurance sports (such as long-distance running and ultramarathons). For regular or short-duration exercise, they are not necessary and increase sugar intake in a similar way to soft drinks. Over time, the composition of sports drinks has also changed, and today they may include unnecessary ingredients such as artificial sweeteners, preservatives, and food colorings.
Sweetened plant-based drinks
Some oat, rice, almond and coconut beverages may contain added sugars, making label reading important.
Flavoured waters
Vitamin Well
Aloe vera drinks
Fruit-flavoured sparkling waters with added sugars
Flavoured waters are often marketed as a healthy alternative to soft drinks, but many of them contain added sugars, fruit juice concentrates, or sweeteners.
Even if their sugar content is lower than that of regular soft drinks, regular consumption can still increase daily intake of free sugars.
Some flavoured waters also contain, among other ingredients, fructose or glucose-fructose syrup.
Although both fructose and glucose are simple sugars, the body processes them differently. Glucose can be used as an energy source by cells throughout the body, whereas fructose is primarily metabolised in the liver. When fructose is consumed in large amounts from sugar-sweetened beverages and other sources of free sugars, it may contribute to fatty liver development, raise blood triglyceride levels, and negatively affect metabolic function (including insulin production).
A 500 ml bottle of Vitamin Well contains 20 g of sugar (which is 5 teaspoons of sugar, including fructose).
A 500 ml bottle of Aloe vera drink (Aleo) contains 39 g of sugar (which is 9 teaspoons of sugar).
Fruit Juice: Healthy or Just Another Source of Sugar?
Unlike soft drinks, 100% fruit juice contains vitamins, minerals, and beneficial plant compounds. However, most of the fibre naturally present in whole fruit is removed during processing.
As a result, fruit juice is digested and absorbed differently from whole fruit. A glass of juice can provide the sugar from several pieces of fruit in just a few minutes, without delivering the same level of fullness.
This does not mean fruit juice is unhealthy. For many people, moderate amounts can fit into a balanced diet. However, for those trying to manage body weight, blood sugar levels, or overall calorie intake, whole fruit is usually the better choice.
But what about nectars and juice drinks?
Beverage Type | Typical Fruit Content | Added Sugar Allowed? |
100% Fruit Juice | 100% | No |
Nectar | Typically 25–50% | Often yes, read the product label for sugar quantity |
Juice Drink | Typically 10–30% | Often yes, read the product label for sugar quantity |
Smoothies and blended fruit drinks
Froosh
Naked Juice
Innocent
Commercial smoothies can contain the sugar equivalent of several portions of fruit while lacking the same satiety benefits as whole fruit, especially when fibre is broken down during processing.
Smoothies should be treated as a meal or snack, rather than a drink. When making smoothie at home:
add vegetables
add nuts/seeds
add protein
to improve satiety and reduce blood sugar spikes. You can learn more about how to create a balanced smoothie that provides satiety from here.
The World Health Organisation (WHO) recommends keeping free sugar intake below 10% of daily energy intake (around 50g per day), with additional health benefits when reduced to below 5% (around 25g per day).
Alcohol: The Overlooked Source of Liquid Calories and Sugar
When discussing liquid sugar, alcoholic beverages are often forgotten. Yet for many adults, alcohol may be one of the largest sources of liquid calories in their diet.
Alcohol provides approximately 7 calories per gram—nearly as energy-dense as fat (9 kcal/g). Alcohol provides calories with little nutritional value.
Many alcoholic beverages also contain significant amounts of sugar.
Alcohol: A Hidden Source of Liquid Calories and Sugar
Examples include:
Cocktails such as Margaritas, Piña Coladas, Mojitos and Daiquiris and Long Island Iced Teas
Premixed alcoholic beverages ("alcopops")- Smirnoff Ice, Bacardi Breezer etc. For example, a 275 ml bottle of Bacardi Breezer Orange contains 22 g of sugar (which is 5 teaspoons of sugar).
Hard seltzers with added sweeteners
Flavoured ciders. For example, a 500 ml bottle of Somersby cider contains 40 g of sugar (which is 10 teaspoons of sugar).
Sweet wines
Dessert wines
Liqueurs such as Baileys, Kahlúa and Amaretto
A single cocktail can sometimes contain as much sugar as a soft drink.
What About Beer and Wine?
Beer and wine are not usually considered high-sugar drinks in the same way as soft drinks or cocktails. However, they still contribute a significant number of calories, both from alcohol itself and, in some cases, from residual sugars.
Most beers contain relatively low amounts of sugar, but they are calorie-dense due to their alcohol and carbohydrate content. A typical pint of beer can contain around 200–250 calories, depending on the alcohol strength and style (lighter beers tend to be lower, stronger or craft beers higher).
Wine generally contains little residual sugar in dry varieties, but calories can still add up quickly. A large glass of wine may contain around 120–200 calories, and sweeter wines (such as dessert wines or some rosé and off-dry varieties) can contain more sugar and therefore additional calories.
While beer and wine are not major sources of added sugar, the alcohol itself provides energy that is not always fully compensated for in the rest of the diet. Over time, regular consumption can contribute significantly to total daily calorie intake without creating strong feelings of fullness.
Why Alcohol Can Promote Weight Gain
Alcohol may contribute to weight gain through several mechanisms:
Additional Calories
Many people consume alcohol on top of their normal food intake.
Increased Appetite
Alcohol can stimulate appetite and reduce inhibitions around food choices, making it easier to overeat.
Poorer Food Choices
After drinking alcohol, people are more likely to choose highly processed foods that are high in fat, sugar, and salt.
Disrupted Sleep
Although alcohol may initially make people feel sleepy, it often reduces sleep quality and can disrupt hormones involved in appetite regulation.
The Hidden Weekend Effect
A person may be very health-conscious during the week but unknowingly consume hundreds or even thousands of additional calories from alcoholic drinks over a weekend.
For example:
Two glasses of wine on Friday
Several beers on Saturday
Cocktails at a social event
These calories can accumulate without creating much fullness or satiety.
Is There a Better Choice?
From a weight-management perspective and overall health perspective, the best choice is to reduce overall alcohol intake.
If alcohol is consumed, lower-sugar options such as dry wines or spirits mixed with sparkling water generally contain less sugar than cocktails, liqueurs, sweet wines, or sugary mixed drinks. However, it is important to remember that even low-sugar alcoholic beverages still provide calories from alcohol itself.
How Sugary Drinks Contribute to Obesity
Several mechanisms help explain the connection.
Poor Satiety
Calories consumed through beverages tend to be less filling than calories from whole foods.
One of the key reasons liquid calories contribute to weight gain is that they bypass many of the body’s natural appetite regulation mechanisms.
Solid foods require chewing, digestion and time to be processed, all of which contribute to satiety signals in the brain. Liquid calories, on the other hand, pass through the digestive system quickly and do not trigger the same fullness response.
As a result, the body does not reliably reduce food intake later in the day to compensate for the calories consumed in drinks.
Excess Energy Intake
People often consume sugary drinks alongside meals rather than instead of food.
Rapid Blood Sugar Response
Sugary drinks are digested and absorbed very quickly because they contain carbohydrates in a “pre-dissolved” form. Unlike solid foods, they require no chewing and very little digestive breakdown before the sugar enters the bloodstream.
As a result, blood glucose levels can rise rapidly after consumption. In response, the body releases insulin, a hormone that helps move glucose from the blood into cells to be used for energy or stored for later use.
Because liquid sugars are absorbed so quickly, they often lead to a sharper and faster rise in blood glucose and insulin compared with the same amount of sugar consumed in whole foods. This is partly because whole foods—such as fruit, legumes, or whole grains—contain fibre and structural components that slow digestion and absorption.
Over time, frequent spikes in blood glucose and insulin may contribute to increased hunger and energy intake. Some research also suggests that habitual high intake of sugar-sweetened beverages is associated with reduced insulin sensitivity and a higher risk of metabolic conditions, including type 2 diabetes.
Another important factor is that liquid calories do not trigger the same satiety signals as solid foods. This means that even after a sugary drink, people often continue eating their usual amount of food, rather than naturally compensating for the extra calories consumed in liquid form.
For this reason, sugary drinks are considered one of the most efficient ways to consume excess calories without feeling full—one of the mechanisms thought to contribute to weight gain over time.
Habitual Consumption
Beverages can be consumed quickly and repeatedly throughout the day, making it easy to accumulate hundreds of additional calories.
Are Zero and Diet Drinks a Better Choice?
This question generates considerable debate.
Compared with sugar-sweetened beverages, Diet Coke, Coke Zero, Pepsi Max and similar products typically contain few or no calories and do not produce the same blood sugar response.
For someone regularly consuming multiple sugary soft drinks daily, switching to a diet version may reduce sugar and calorie intake.
However, this does not automatically make these beverages health-promoting.
Researchers continue to investigate whether artificial sweeteners may influence:
Appetite regulation
Food preferences
Gut microbiota composition
Metabolic health
The evidence remains mixed.
Experts such as Tim Spector generally encourage people to focus on reducing the overall preference for intensely sweet foods and drinks rather than replacing sugar with increasing amounts of artificial sweeteners.
Why Sugary Drinks Matter Even More for Children
Reducing sugary drinks is particularly important during childhood. Taste preferences begin to develop early in life, and children who regularly consume sweetened beverages may become accustomed to very sweet flavours, making water and less sweet foods seem less appealing.
Sugary drinks can also easily become a daily habit. Because children have lower energy needs than adults, a single can of soda or other sweetened beverage can contribute a much larger proportion of their recommended daily sugar intake. Over time, this may increase the risk of excess calorie intake, weight gain, tooth decay, and poor dietary habits.
Helping children develop a preference for water and other low-sugar beverages from an early age can support healthier eating habits that may last into adulthood.
What Should You Drink Instead?
The healthiest beverages remain relatively simple:
Water
Sparkling water
Herbal tea
Unsweetened tea
Coffee without added sugar
Kombucha (check the sugar content if you purchase it from a store)
If you enjoy flavoured drinks, try adding:
Fresh berries
Citrus slices
Mint
Cucumber
Fresh herbs
These can provide flavour without large amounts of added sugar.
Final Thoughts
The aim of this article is not to convince you to give up all sweetened drinks or to make you feel that a single soda, juice, or iced tea will harm your health. Rather, the goal is to help you notice how large a proportion of our daily sugar intake can come from beverages.
Many people pay attention to sweets, cakes, and biscuits, but are not aware that a significant amount of sugar may actually come from soft drinks, energy drinks, flavoured waters, juices, nectars, sports drinks, smoothies, or alcohol. Since “liquid” calories do not usually create the same sense of fullness as solid foods, it is easy to consume more than the body actually needs.
This is especially important to consider in children and young people. Taste preferences develop early, and the more frequently very sweet drinks are offered, the more normal the sweet taste becomes. The good news is that taste buds adapt. If the consumption of sweetened drinks is gradually reduced, many people will over time start to prefer less sweet drinks and foods.
Take a moment to review your diet. How many sweetened drinks and sugary foods are part of your or your family’s typical week? Is there a drink you could consume less often, in smaller amounts, or replace with water, herbal tea, or another less sweet alternative?
Often, no major changes are needed. Even one or two small steps can, over time, help reduce excess sugar intake and support a healthier body weight, better metabolic health, and overall well-being.
From a health perspective, the goal is not perfection, but awareness and consistently making better choices.
If you want to improve your diet, reduce the intake of added sugar and need professional guidance, don't hesitate to reach out to me to schedule a personalised nutrition counselling session at info@katrinpeo.com.
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