Cut the Waist

Cut the Waist

Illustrative photo for 'Cut the Waist'
The philosophy of Cut the Waist is to prevent obesity related ill health through education resources

Replacement meal plans using portion-controlled meal products

Evidence suggests that meal replacements using commercially available portion-controlled meal products can strengthen the dietary adherence component of weight loss programmes. The structure and convenience of a meal replacement strategy can be extremely helpful approach for some people to facilitate stabilisation of eating behaviour. A meal replacement approach should therefore be considered as part of any comprehensive weight management intervention, and should be regarded as being in keeping with an individual tailored advice and support strategy for people who strive to achieve weight management success and may benefit from readily available portion and calorie-controlled meals.

Health care professionals have given little attention to the potential of the meal replacement approach in the management of overweight and obesity. This may relate to concern about the value of meal replacements in long term weight management. Over recent years however, a number of randomised controlled trials have supported the longer term efficacy of meal replacements and Dietitians in Obesity Management (DOM UK) support meal replacements as one of a range of dietary treatment options for use within comprehensive weight management programmes. Despite this emerging evidence base and support of a meal replacement approach as a useful strategy for some people, it is unclear to what extent this research has filtered through and influenced practitioner's opinions on the use of meal replacements in the management of overweight and obesity. This may reflect a lack of knowledge of exactly what constitutes a meal replacement approach and lack of appreciation of positive weight loss outcome data achieved via this approach.


As a working definition, meal replacements are considered to be portion controlled products which are mineral and vitamin fortified designed to replace one or two meals in the day (generally breakfast and lunch) allowing preparation of one low calorie (typically evening) meal using standard food and supplementing with fruit, vegetables and calorie controlled product snacks.

A meal replacement approach is different from the very low calorie diets in that the calorie level of these diets is at least 900kcal/day (and typically 1200-1600kcal), thus reducing the need for medical monitoring, and at least some meals each day are consumed as regular food. Unlike very low calorie diets, meal replacements are not designed to be a complete source of nutrition, and are not usually recommended for use without inclusion of foods in the diet. Commercially available meal replacements such as SlimFast come in the form of liquid shakes, soups, bars and portion controlled meals.

An example of a typical meal replacement approach

The replacement meals contain around 200-250kcal and the normal meal around 600kcal.

Typical calorie count for a day's eating 1,200

Breakfast: Milk shake replacement meal

Snack: Apple

Lunch: Milk-shake replacement meal

Evening meal: Grilled chicken, baked potato, 2 servings of vegetables, gravy, banana

To drink: 6-8 glasses of water or calorie controlled drinks

Thus two meals are swapped for the meal replacement – in this case a nutritionally balanced and calorie counted shake-type drink, but alternatives such as calorie counted bars, soups and prepared meals can also be used.

This combination of food based meals and meal replacement products such as liquid shakes, bars and pre-prepared meals is sometimes referred to as a partial meal replacement plan (PMR).

Advantages and disadvantages of meal replacements


Commercially available products provide fixed-portion and calorie amounts which takes the guesswork out of portion control and estimating calories.

Are convenient to use and widely available.

Emphasis on regular eating to stablise eating and facilitate dietary adherence.

Pressure of food selection reduced whilst allowing normal food in diet to allow an element of choice.

Reduce contact with problem foods.

Satisfy appetite through limiting range of food choices.

May encourage weight loss maintenance and appear to be at least as effective as conventional dietary approaches in this regard.


Boredom with use of meal replacement products over time.

Limitation of outcomes and evidence for "off the shelf" unsupported consumer usage. Meal replacement research and outcomes studies often involve provision of meal replacement products free of charge to participants which is likely to increase compliance. Participants of clinical trials and research studies often receive the benefit of ongoing support to develop their skills in the selection of food types and portion sizes as well as benefitting from ongoing monitoring as part of the trial. There is a need to evaluate the real life outcomes of using a meal replacement approach within a standard UK healthcare setting with the limited resources and time that are usually evident in these situations.

Cost implications – may not be considered a viable option for lower socio-economic groups.

Evidence for partial meal replacement strategy

1 Randomised controlled trial as part of a well supported programme

Ditschuneit1 and Fletchner-Mors2 undertook a long term randomised trial involving 100 subjects with a mean BMI of 34kg/m2 comparing a conventional dietary treatment with meal replacement approach over the short term [3 months] with progress monitored for the next 4 years.

For the first 3 months one group [n=50] was treated with a conventional low calorie diet of 1200-1500kcal/day (Conventional Food CF), whilst the other group were advised to replace two of their three meals each day and with liquid shakes and eat one self-selected meal of 600-900kcal (MR-2)

Both groups were asked to keep food diaries and monitored monthly by the nutritionist.

For the next four years, both groups were given meal replacements and asked to use these in place of one meal and one snack each day.


After the three month weight loss phase, the conventional food group (CF) lost 1.5±0.4% body weight whereas the meal replacement group (MR-2) lost 7.8±0.5% [p<0.001]

Over the next four years weight loss was maintained in both groups with a mean weight loss of 3.3±0.8% and 8.4±0.8% for groups CR and MR-2 respectively. This study suggests that meal replacements may encourage weight maintenance and in this instance produce better weight loss than a conventional low calorie diet over 12 weeks.

Graph: Meal replacements enhance initial and long-term weight loss

2 Community based intervention with minimal related support

Rothaker3 devised a minimal intervention weight control programme involving provision of free meal replacement products to 158 overweight men an women in an American rural community. This study demonstrates the potential of an easily adopted minimal intervention weight management approach using meal replacements.

During this 5 year study, participants were weighed twice per year and were instructed to replace two meals per day with liquid shakes during the weight loss phase and to help maintain their lost weight to either use one meal replacement each day or to weigh themselves on a daily basis. If weight was regained the advice was to start using 2 meal replacements each day once again.

Three control subjects were selected to match each meal replacement participant for age, BMI, race and gender.


After 5years mean weight change in the men using meal replacements was -5.8±5.4kg and in the women -4.2±6.9kg. By comparison male controls gained 6.7±10.2kg and females gained 6.5±10.7kg, illustrating the high level of background weight gain over a 5 year period.

3 Meta-analysis of six randomised controlled trials

Haymesfield has examined the findings of six randomised controlled trials in which the meal replacement approach was compared to a more conventional food based dietary treatment.

Four of the studies were carried out over one year, once for three months and one for four years. Meta-analysis of the study results demonstrated significantly greater weight loss in the meal replacement group compared to the conventional dietary treatment, amounting to 2.54kg greater weight loss in the meal replacement group at three months and 2.43kg greater weight loss at one year. They concluded that the use of a meal replacement approach could "safely and effectively produce significant and sustainable weight loss and improve weight-related risk factors of disease"4

Interestingly, no difference in drop out rate was observed between the meal replacement group and conventional dietary treatment group at 3months.However a much lower drop out rate was observed at one year in the meal replacement group suggesting that a meal replacement approach improved dietary compliance in comparison to a conventional dietary approach.

4 Meal replacements and obesity management guidelines

a. The DOM UK position statement on meal replacements:

1 We consider that there is sufficient evidence to support the inclusion of meal replacement approaches as one of a range of possible dietary treatments for the management of overweight and obesity.

2 A number of studies have demonstrated the short-term effectiveness of meal replacements showing them to be as least as effective as conventional dietary treatments.

3 Uncontrolled studies with longer term follow up suggest that meal replacements may encourage weight maintenance.

4. Most studies have used meal replacements as part of a comprehensive programme with support and education from health professionals. Less is known about the value of "off the shelf" unsupported usage.

5. More information is needed about which patients do best with this dietary treatment and how to integrate meal replacements within the management of overweight and obesity in the UK healthcare and community settings.

6. Studies do support the safety of using meal replacements in overweight and obese people with type 2 diabetes although, as with weight management in general, outcomes tend to be poorer compared to those without diabetes.

7. Little is known about how effective this dietary treatment will prove to be in obese people with BMI>45kg/m2 as meal replacement studies to date have included subjects in lower BMI categories.

b. Meal replacements and Australian clinical guidance

As part of the background research on meal replacement to establish recommendations as part of the Australian Clinical Guidelines on the management of overweight and obesity, four studies were evaluated comparing meal replacement treatment with conventional low calorie diets over a 1-5year period. In these studies a mean weight loss of 6kg was found in the meal replacement group, compared to a 1.4kg increase in weight in the conventional low calorie diet group. The Australian Clinical Guideline recommendation* was that "clinically significant weight loss can be achieved using meal replacement programmes"5

* [level B evidence: obtained from at least one properly designed randomised controlled trial]

c. Meal replacements and UK clinical guidance (NICE Guidelines)

National Institute of Clinical Excellence (NICE) Guidance on Obesity Management CG43 December 2006 states "There is no strong evidence to support the use of meal replacement products over a standard low calorie diet", citing two studies, Rothaker3 and Ahrens et al6

The objective of the interesting study by Ahrens at al was to compare meal replacement (MR) program with a reduced calorie diet (RCD) for weight management using the pharmacy as the setting and the pharmacist as the point of contact for dietary advice. Patients were randomised to a MR plan of traditional RCD plan. Patients were followed up for a 3-month period of active weight loss and a 10-week period of weight maintenance. Patients returned every 3 weeks for follow up with the pharmacist for a total of 13 visits.


During the active weight loss phase, the MR (n=45) and RCD (n=43) lost a significant amount of weight, although no statistical difference was found between the groups (4.9±0.3kg MR versus 4.3±0.3 RCD; P=0.16). In the weight maintenance phase, the MR group lost 0.7±0.4kg and the RCD group lost 0.9±0.4kg (P=0.60). Significant improvements were observed in waist circumference, systolic and diastolic blood pressure and triglyceride levels.

The study by Ahrens et al concluded that successful weight management can be achieved in a pharmacy setting. Both meal replacement and reduced calorie diets were effective.

Has NICE got it right with regards meal replacements?

It is unclear why NICE cites the study by Rothaker to support their opinion that "there is no strong evidence to support the use of meal replacements over a standard low calorie diets", as this study demonstrates successful weight reduction with a meal replacement approach over a 5 year period against a background of weight gain amongst the male and female control groups.

The NICE guideline conclusion with regards meal replacement contrasts with the meta-analysis by Haymesfield whereby "All methods of analysis indicated significantly greater weight loss in subjects receiving the PMR plan compared to the RCD group."4 Depending upon the analysis and follow up duration the PMR group lost approximately 7-8% bodyweight and the RCD group lost approximately 3-7% bodyweight. A pooling analysis of completers showed greater weight loss in the PMR group of 2.54kg (P<0.01) and 2.63kg (P<0.01) at 3 month and 1year periods respectively.

The drop out rate for PMR and RCD groups was equivalent at 3 months and significantly less in the PMR group at 1year.

The conclusion by Haymesfield and his colleagues was that this first systematic evaluation of randomized controlled trial utilising PMR plans for weight management suggests that these types of interventions can safely and effectively produce significant sustainable weight loss and improve weight-related risk factors of disease.

Another study to support the use of meal replacements over conventional low calorie diets is provided by the results of a study by Noakes et al who demonstrate that meal replacements are equally as effective for losing weight compared with conventional but structured weight loss diets. The investigators noted that dietary adherence and convenience were viewed more favourably by participants who consumed meal replacements than those in a conventional weight loss programme.7


NICE guidance on the prevention, identification, assessment and management of overweight and obesity in adults advocates:

"Dietary advice should be individualised, tailored to food preferences and allow for flexible approaches to reducing calorie intake"

Furthermore, theme 5 of "Healthy Weight Healthy Lives" champions the concept of "individual tailored advice and support" with regards approaches to weight management.

With this in mind it would therefore seem appropriate to advocate a DOM UK stance towards meal replacement approaches:

"We consider that there is sufficient evidence to support the inclusion of meal replacement approaches as one of a range of possible dietary treatments for the management of overweight and obesity."
"More information is needed about which patients do best with this dietary treatment and how to integrate meal replacements within the management of overweight and obesity in the UK healthcare and community settings."


1 Ditschuneit HH, Fletchner-Mors M, Johnson TD, Adler G. Metabolic and weight loss effects of a long-term dietary intervention in obese patients. Am J Clin Nutr 1999; 69: 198-204

2 Fletchner-Mors M, Ditschuneit HH, Johnson TD, Suchard MA, Adler G. Metabolic and weight loss effects of long term dietary intervention in obese patients: four year results. Obesity Research 2000; 8[5]: 399-402

3 Rothaker DQ. Five year self management of weight using meal replacements: Comparison with matched controls in rural Winconsin. Nutrition 2000; 16: 344-348

4 Heymsfield SB, van Mierlo CAJ, van der Knaap HCM, Heo M, Frier H. Weight management using a meal replacement strategy: meta and pooling analysis from six studies. Int J Obes 2003; 27[5]: 537-49

5 Australian Clinical Guidelines

6 Ahrens RA, Hower M, Best AM. Effect of weight reduction interventions by community pharmacists. J Am Pharm Assoc 2003; 43: 583-9

7 Noakes M, Foster PR, Keogh JB, Clifton PM. Meal replacements are as effective as structured weight loss diets for treating obesity in adults with features of metabolic syndrome. J Nutr 2004; 134: 1894-99