A weight loss expert has cautioned that Britain's most popular summer beverages could be undermining efforts to shed pounds, despite appearing to be healthier alternatives.

Professor Franklin Joseph, consultant physician and head of Dr Frank's Weight Loss Clinic, warned that drinks like iced coffees, smoothies and fruity cocktails can contain hundreds of hidden calories whilst providing minimal nutritional benefit.

"People often underestimate how much liquid calories add up, especially in the summer when you're socialising more and it's hot outside," he said.

The physician notes that these beverages can accumulate significant calories, sugars and concealed fats, particularly when consumed regularly during warmer months.

Fruity spritz-style drinks like Aperol Spritz can contain 200-300 calories per serving

According to Prof Joseph, the most problematic beverages include frozen cocktails such as piña coladas and strawberry daiquiris, which contain over 400 calories per glass.

Fruity spritz-style drinks like Aperol Spritz can contain 200-300 calories per serving, with alcohol-free versions often high in sugar.

He warned that even mocktails without alcohol can reach 250 calories per serving due to added syrups and juices.

Iced lattes made with milk and syrup, on the other hand, contain approximately 300 calories, comparable to a small meal.

Fruit smoothies can pack up to 350 calories with elevated sugar content that increases hunger, whilst kombucha may contain 50-100 calories per bottle with hidden sugars.

"These drinks might seem refreshing and light, but they're often loaded with hidden calories that don't fill you up," Prof Joseph said.

He explains that whilst solid foods provide satiation, liquid calories pass through the system quickly without triggering the same fullness signals.

"Over a week or two, the impact on your fat loss progress can be significant."

The physician also highlighted that freshly squeezed juices contain around 150 calories per glass with minimal fibre to maintain satiety, whilst full-fat fizzy drinks pack 150-200 calories per can with sugar that stimulates further cravings.

The best option for weight loss is always water

"It's easy to think you're making healthy choices - but the drinks you're having between meals could be the very thing stopping fat loss."

Prof Joseph recommends simpler alternatives to support weight loss objectives.

"The best option is always water - plain, sparkling, or infused with fruit, herbs, or lemon for flavour," he said.

He also suggests herbal teas, black coffee and iced water with lime as suitable choices.

For those consuming alcohol, the physician advises selecting lighter options such as white wine spritzers, gin with slimline tonic, or single spirits mixed with soda water.

"Enjoy a treat occasionally, but keep it in check," he said. "Consistency is key for fat loss - and being aware of hidden calories is half the battle."