Meal replacements for weight management
- To gather and analyse evidence for the effectiveness of meal replacements as weight loss aids
- To estimate the weight people lose in the 12 months after being encouraged to use meal replacements, relative to other ways of losing weight.
- To identify factors associated with successful weight loss using meal replacements
- To draw on the experience of providing weight management advice in primary care to develop a programme including meal replacements that healthcare professionals, such as GPs or practice nurses could recommend for people to follow at home.
Why this is important:
Almost two-thirds of adults in the UK are overweight. There is good evidence that being overweight increases the risk of developing a range of different chronic (long-term) diseases, including:
- type 2 diabetes;
- high blood pressure;
- hearts attacks;
- colon cancer; and
Almost half of English adults are trying to lose weight at any one time but the amount of weight they typically lose is very small. We know that losing even 5% of initial body weight can bring significant health benefits so it is important that we find new ways to help people succeed. Research shows that people are more likely to be successful if they receive professional advice.
Some research shows that using meal replacement products may be associated with increased weight loss.
Meal replacements are portion-controlled foods, sometimes part of a branded diet programme, which replace one or more regular meals. Meal replacement products have become widely available in shops and supermarkets but there has been no recent ‘systematic review’ of their use for weight-loss.
A ‘systematic review’ summarises the best available research on a specific topic. In this case meal replacements for weight loss. It’s a rigorous and transparent way of gathering together all the available evidence and analysing it to give a ‘state-of-the-art’ overview of what we know about that topic, to help guide future activities or research.
If meal replacements products are shown to lead to successful weight loss it may be that healthcare professionals could advise people how to use them to achieve greater success in their weight loss efforts at home.
To examine how effective meal replacements are for weight loss in overweight and obese adults, we will conduct a systematic review.
Once we have identified all the studies to include in the systematic review, they will be checked for biases which could skew their results or make them unreliable in some way. For example, studies where lots of people dropped out of a trial (‘attrition’ bias). Attrition bias can make an intervention look like it works better than it really does – it may have worked for those who stayed in the trial, but not those who left (who may have left because it wasn’t working for them).
We will then statistically analyse the data in all the remaining studies to determine the effectiveness of meal replacements for weight loss.
The main thing we will be looking for (the 'primary outcome') will be how much weight people lose on average between starting meal replacements (the ‘baseline’) and 12 months later.
However, we will also look at 'secondary outcomes', such as weight change at six months or beyond 12 months, if this is reported in the study papers. We will also examine other factors, such as changes in the rates of diabetes, cardiovascular risk and quality of life.
We will also look for information in the reports of the studies to help us identify factors associated with successful weight loss.
If we find evidence that meal replacements are effective, we will use our knowledge of weight management in primary care together with the evidence from our review to develop a programme and resources that health professionals can use to support patients to lose weight.
This will include considering what existing evidence tells us about what works, for whom, and in what circumstances. This will help us to make our resources as applicable to as many people and situations as possible.
We will invite our patient and public involvement (PPI) group and practice nurses to comment on and give feedback on the content and format of these resources.
How this could benefit patients:
If we can develop a programme and resources that nurses feel confident to deliver and patients think is acceptable to them we will plan a formal trial. The trial will see if this meal replacement approach to weight loss can help more people to lose more weight than the advice usually provided by doctors or nurses in GP surgeries.
Effective and proven strategies for weight loss have the potential to improve the quality of life and a programme like this could be used by large numbers of people. Successful weight loss can reduce the risk of a host of different diseases, from strokes to diabetes. In turn, this will reduce people’s need to use NHS services and medication.
This has the added benefit of freeing up resources, in terms of health professional time as well as financial, for other patients and conditions.