As I sit here waiting for my flight, watching people navigate the vending machines, I’m reminded of how drastically our drink options have expanded. From sugar-laden soft drinks to reconstituted fruit juices and caffeinated energy drinks, most of these beverages offer nothing but kilojoules (calories) without significant nutritional benefit.
The issue is liquid kilojoules—and they can be a major roadblock when it comes to maintaining a healthy weight. Here’s why it’s best to get most of your kilojoules from solid food.
1. Liquids Bypass Natural Hunger Cues
Our bodies are designed to process most of our kilojoules from solid food. Chewing initiates digestion and signals to the brain that food is on its way, which helps manage appetite. When you drink your kilojoules, you bypass these mechanisms, often consuming more kilojoules without feeling full.
Research shows that liquid calories don’t promote the same feelings of satiety as solid foods, leading to overeating. Whether it’s a sugary soft drink or fruit juice, you're more likely to eat your usual amount of food on top of these extra liquid kilojoules.
2. Sugary Drinks: Empty Kilojoules
Soft drinks, energy drinks, and even some fruit drinks provide a large dose of sugar with little to no nutritional value. Consuming sugary drinks has been linked to increased risks of obesity, type 2 diabetes, and heart disease. While fruit drinks may appear healthier, they often contain added sugars and additives that further diminish their nutritional value.
3. Pure Fruit Juice: A More Complex Story
While sugary beverages are a clear negative, recent research presents a more nuanced picture of 100% fruit juice. According to a 2024 umbrella review of systematic reviews and meta-analyses, moderate consumption of 100% fruit juice is not strongly associated with weight gain and may, in fact, offer several health benefits.
The review found that regular consumption of 100% juice can contribute to improved nutrient intake and has been linked to beneficial effects on cardiovascular health, inflammation, and blood pressure.
For example, the consumption of 100% juice was associated with reductions in systolic and diastolic blood pressure, as well as improvements in vascular function. Some phytonutrients in juice, such as polyphenols and antioxidants, appear to play a role in these positive outcomes by enhancing nitric oxide bioavailability, improving blood flow, and reducing inflammation.
Although 100% fruit juice does contain natural sugars, its impact on blood sugar levels and insulin resistance was found to be minimal in short-term studies. Moreover, the antioxidants and vitamins found in 100% juice—like vitamin C and potassium—help support overall health. Therefore, moderate amounts of 100% juice (about 150-250 mL per day) can be part of your healthy diet.
That said, it’s still wise to prioritise whole fruits over juice because whole fruits contain more fibre, which helps with satiety and supports gut health.
4. The Pitfalls of Diet Drinks
Diet drinks might seem like a safer option because they are calorie-free, but they come with their own set of issues. Artificial sweeteners can trick your brain into expecting sweetness, which may make it harder to reduce sugar cravings. Furthermore, these drinks are still acidic, which can erode tooth enamel over time.
5. Liquid Kilojoules and Nutrient Deficiency
Relying on sugary or artificially sweetened drinks as a major source of kilojoules risks leaving you overfed but malnourished. These beverages are low in essential nutrients, meaning you could consume more kilojoules without getting the vitamins, minerals, and fibre your body needs to stay healthy and full.
6. Water is Still Best—And Let's Talk About Plastic
The best drink for hydration and health is plain water. It’s calorie-free, nutrient-free, and free of harmful additives. But as we move toward more sustainable choices, consider the impact of single-use plastics. Bottled water, while convenient, contributes to plastic pollution. Instead, opt for a reusable water bottle made from stainless steel or glass. Fill it up with tap water, which is just as hydrating and eco-friendly. Adding fresh herbs, lemon slices, or cucumber can make your water more exciting while still keeping it healthy.
The Bottom Line
Getting too many kilojoules from liquids—whether from sugary soft drinks, reconstituted fruit juices, or even diet beverages—won’t help you stay lean or healthy. Stick to water as your go-to beverage. And when possible, choose reusable bottles to reduce plastic waste and do your part for the planet.