Whether you’ve seen them in about every supermarket health-food aisle over the decades or you’ve been hit with The Man Shake ads of late – meal replacement shakes remain a well-marketed way to shed kilos. But does the science behind their advertised weight loss benefits stack up?
If you’re wondering whether weight loss shakes work for men and if you should try them, here’s what you need to know.
What are meal replacement shakes and how do they work?
Meal replacement shakes work as their name suggests – they’re a premixed drink or powder formula you mix with water or milk that you can consume to replace a regular, meat-and-three-veg meal. They have different purposes including weight loss, weight gain, convenience or boosting nutrient intake.
Meal replacement shakes formulated for weight loss are low in energy (which is measured in kilojoules or calories). Drinking a weight loss shake instead of eating a higher kilojoule meal will help to reduce your overall energy intake. This can lead to weight loss. Weight loss shakes encourage an energy deficit, which means you take in fewer kilojoules than you use in exercise and daily activities.
They’re often used as part of low energy diets (LED), which is when you aim to reduce total daily energy intake to 4200 to 5000 kJ (1000 to 1200 kcal) or very low energy diets (VLED), which is when you’re aiming for an energy intake of less than 3300 kJ/day (800 kcal/day).
What are weight loss shakes made of?
Weight loss shakes are mostly protein-based from milk or soy-based powders that are mixed with water or skim milk. They usually contain few carbohydrates and are supplemented with vitamins and minerals.
Do weight loss shakes work?
The short answer is that we don’t really know. A systematic review found that meal replacement low-energy diets were more effective for weight loss than food-based low-energy diets, BUT:
Regardless of their effectiveness, meal replacement shakes are not suitable for long term use.
“I don’t recommend weight loss shakes because they’re a band-aid,” says Accredited Practising Dietitian, Joel Feren. “They can help you shift kilos fast, but they are not sustainable, and they don’t teach you what to eat or how to form a healthy relationship with food. The best diet is sustainable and non-restrictive. I don’t think shakes tick either box.”
Can you lose weight just drinking weight loss shakes?
Yes, you can lose weight using meal replacement shakes. But it’s not a long-term weight management solution. If you’re using weight loss shakes you should also get guidance on your overall nutrition, aiming to meet the Australian nutrition guidelines and the recommended amount of exercise each week.
What are the side effects of weight loss shakes?
There are a few downsides that come with downing meal replacements.
Nutritional deficiencies
“You need to get enough fibre, folate, B vitamins, iodine, iron, zinc and other essential nutrients, so that you don’t end up with some sort of nutrient deficiency because your diet is so restricted,” Feren says. Not getting enough fibre in your diet doesn’t only affect your digestive health. Adequate fibre intake is essential for heart and brain health.
Weight regain
If you don’t work on your eating and exercise habits, weight will return once you stop drinking the weight loss shakes.
Social issues
Restricting your eating isn’t fun, and can impact your social life, relationships and emotional health.
How often should you drink weight loss shakes?
Firstly, Australia’s National Health and Medical Research Council advises that anyone who uses meal replacements as a weight loss strategy should do it with the help of a healthcare professional to ensure you use them safely. Some people are recommended to replace one meal a day, some use them as part of a fasting period like the 5:2 diet and some need them to replace every meal for substantial weight loss prior to surgery.
So, what’s the best way to kick-start weight loss?
“I like to encourage the baby-step approach,” Feren says. “Focus on small but significant dietary modifications that can lead to lasting change.”
That could be swapping out sugary drinks for water, including more alcohol-free days, or aiming to get your two serves of fruit and five serves of veggies a day.
“Set smart and achievable goals and focus on changes that set the foundations for a healthier future.”
If you want to lose weight, start by chatting with your doctor. They can help you get the support you need to make sustainable changes.
