5 Simple and Effective Strategies for Dropping 5kg in a Month

Are meal replacement shakes effective for weight loss?

Meal replacements (MR) are generally not recommended in clinical guidelines for the management of overweight. In Australia, only Very Low Energy Diet (VLED) meal replacement programs are included in national guidelines for health professionals. VLED diets provide less than 3300kj (800kcal) per day and are often provided within a total diet replacement using specially formularised shakes and ideally with agreement from your doctor. They are not for the faint of heart and require regular medical appointments to monitor your health and well-being due to possible changes to your blood pressure and vitals while losing weight.    These are commonly used before bariatric surgery or where rapid weight loss is required before surgery or for health needs.

Meal replacements on the other hand are foods or drinks that are used to replace one or more meals with the intention of reducing your overall calorie intake for the purpose of weight loss or weight maintenance following a period of weight loss. Meal replacements can include soups, shakes, bars as well as portion-controlled ready-made meals. There has been some uncertainty about the long-term effectiveness of meal replacements which may explain why national guidelines don’t mention them with regard to weight management.

So are meal replacement shakes worthwhile? To help me answer this question, I have considered the evidence in a 2018 systematic review and meta-analysis conducted by Oxford University in the UK on the effectiveness of meal replacements for weight loss. A systematic review is a very high-quality study that looks at all the evidence available and then re-analysis the data as it if were one large study to provide more confidence in the results.

The study looked at 23 studies with almost 8000 adults included in the data. This study found that overall, the meal replacement products lead to 1.5kg extra weight loss at 1 year compared to if the person tried to lose weight on their own. The research also showed that this difference in weight loss was maintained for up to 4 years.  

This doesn’t sound like a lot but evidence and experience suggest that a goal of 5-10% of your weight over a year is a realistic aim when making diet and exercise changes.  This would mean a 90kg woman could realistically lose around 5-9kg over 12 months. Many people start a weight loss plan feeling highly motivated and enthusiastic about their weight loss goals, but if you consider that weight loss happens often as slowly as you gained it, then around 1-4kg per month is usually the average over the whole weight loss period. There may be months it is faster (usually in the beginning) and then some months it will be slower or at a standstill (birthday month, Xmas, Easter, holidays etc). Other factors such as your starting weight, height, age, activity level, medical conditions, medication and genetics can influence how fast or slowly you lose weight.  


With that weight loss expectation in mind, the research looked at the likelihood someone would reach 10% weight loss over a year when including meal replacements in their plan. The results of this analysis found that people were twice as likely to reach 10% weight loss when using meal replacements and this increased to 8 times as likely to reach 10% weight loss when regular support appointments were included (such as from a dietitian) compared to self-directed diet changes.


Meal replacement shakes are great for replacing meals at the times of day when you are most busy like breakfast or lunch.  These can be very convenient and for many people may be an opportunity to eat something rather than nothing.


Replacing dinner can also be a great option as this is also the time of day when most of us are relaxing and therefore don’t require a big meal to fuel the next few hours. The time saved on cooking dinner could then be used to plan and prepare your meals for the next day so that you eat more food when your activity and energy needs are highest. Obviously, dinner is also a time of day that families and friends get together to share a meal, and that is an important part of the joy and pleasure of eating which shouldn’t be missed. So, it is ok to be flexible about when you replace a meal. Find out which meals will work on which days.

January 10, 2024