Is there a science to smoothies?

Smoothies are a popular go-to drink or meal for just about anyone. In a world focused on convenience, smoothies are top of the list when it comes to quick breakfast ideas. There is no arguing the popularity of a good smoothie, with the industry valued at 6.8 billion dollars by the end of 2022 (1). But like many convenience foods, few people understand what they are consuming. We ask… is there a science to the smoothie? Often, people supplement their breakfast or lunch-time meals with a smoothie, which can result in a calorie surplus as a smoothies commonly contain a fair amount of calories and can constitute as a meal in and of itself. The nutritional value of smoothies can vary drastically depending on their ingredients and portion sizes.

We compare two local crowd-favourites at two popular smoothie retailers. It's without a doubt that these delicious drinks are so popular because they taste great, and definitely can substitute as a healthier alternative to other types of drinks such as milkshakes, soft drinks or energy drinks.

The popular Peanut Butter Blue smoothie from Nu, has 1211 kJ / 302 calories with 7g protein, 36g carbohydrates and 14g fat per single small serving, which equates to 1 portion of protein, just over 2 portions of carbohydrates and 3 portions of fat. It also has 23.4g of sugar, which is almost 5 teaspoons.	Comparing this to the Kauai large peanut butter bomb, which has 3196 kJ / 760 calories, with 46g protein, 53g carbohydrates and 40g fat. That’s the equivalent of 6 portions of protein, 3 portions of carbohydrates and 8 portions of fat.

It’s important to consider the fact that most people don’t understand that a smoothie can pack the equivalent of an entire meal, or two, and will often pair their smoothie with a wrap or sandwich, very quickly increasing their calorie consumption for the day.  The best advice when it comes to smoothies is to make them at home to avoid ingredients high in sugar and saturated fat. When making your own smoothies at home, here a few suggestions on what to include. Always start with a good quality protein (2), this can be 100ml LF plain yogurt or milk, 10g whey or plant protein, or half a cup of fat-free cottage cheese. Adding two servings of carbohydrates can help with energy levels (2).

Make sure to include high fiber, low sugar options such as 20g rolled oats, 25g All Bran flakes and 1 fruit, such as 1 banana, 100g mango or 10 strawberries. It’s a great idea to add in some veggies if you can, such as a handful of spinach to increase healthy phytonutrients (3). Lastly add in a health fat, such as 20g avocado, 2 teaspoons sugar free peanut butter or 5 almonds (2). Don’t forget to add in some flavour, from cinnamon or vanilla extract.

To bring you the most evidence-based and cutting information in the fields of sports and exercise science and health, SSISA works alongside the UCT Research Centre for Health through Physical Activity, Lifestyle and Sport (HPALS) to disseminate the latest research.  HPALS research focuses on optimizing human performance and promoting health and well-being through physical activity, sports participation, healthy eating and good sleep hygiene.  Their work begins at the DNA, to the human performance laboratory and ultimately to the community. To read more about the Health through Physical Activity, Lifestyle and Research Centre, Division of Physiological Sciences at the University of Cape Town, please see the HPALS website or email Ayesha Hendricks for more information about applications for MSc/PhD research programmes.

To get in touch with the Sports Science Institute of South Africa Group for Research Implementation and Translation (GRIT) Research Consultants, get in touch with Warren Lucas at research@ssisa.com or call 021 650 5728 for enquiries. Read more about the SSISA GRIT Team here.

Yours in Sports Science,

Sports Science Institute of South Africa

References:

1. Market Analysis Report. Smoothies Market Size, Share & Trend Analysis Report By Product (Dairy-based, Fruit-based), By Distribution Channel (Smoothie Bars, Restaurants, Supermarkets & Convenience Stores), By Region, And Segment Forecasts, 2022 - 2028. 2020.
2. Gov D. Dietary Guidelines for Americans Make Every Bite Count With the Dietary Guidelines [Internet]. Available from: https://www.dietaryguidelines.gov/
3. Metcalf E. Phytonutrients. 2022.