The main finding of the study, that set out to mirror a real world setting where individuals buy meal replacements from a supermarket or pharmacy, was that consumption of 2 meal replacements for 3 months and 1 meal replacement for a further 3 months led to greater weight loss of approximately 2
kg (5%) and a 0.11% decrease in HbA1c compared with control subjects who used a commercially available weight loss book. However on intention to treat analysis which reflects real world use of the meal replacements with many people discontinuing treatment by 6 months there was no difference seen in either weight or HbA1c compared with the weight loss book. If the meal replacements were purchased rather than provided, then drop out rates may have been even higher. There were no benefits on LDL cholesterol or triglyceride but HDL cholesterol was increased compared with the diet book group. Fasting triglyceride was not abnormal to begin with and the 5% weight loss was too low to alter it significantly. Fasting glucose was decreased to a small degree in both groups reflecting reduced food intake. The overall weight loss in the meal replacement group of 5.5
kg in those who completed the study is clinically significant as is the fall in HbA1c of 0.3% from baseline and the changes are comparable to those seen in other studies [
9–
14].
Meal replacements are used as a weight loss strategy in people with and without type 2 diabetes and have become a strategy of choice when substantial weight loss is needed [
9–
11]. In a systematic review of controlled trials of lifestyle interventions Brown et al. observed that when meal replacements were added to a low-fat diet there was a significant improvement in weight loss of 5.4
kg [
10]. In people with diabetes meal replacements are most often used as part of a multidisciplinary weight management program as they are a viable and potentially cost-effective solution to weight management in type 2 diabetes [
9].
Intentional weight loss in people with diabetes is very effective at reducing cardiovascular risk. In a systematic review Aucott et al. (2004) found that people with diabetes who lost weight intentionally significantly reduced their mortality risks by 25% with weight loss of 9–13
kg being most protective [
12]. Therefore development and use of effective weight loss strategies are very important in people with diabetes.
A number of studies have examined the use of meal replacements in this context [
13–
15].
In a study of 57 subjects with type 2 diabetes comparing meal replacements with an exchange diet plan for 12 weeks Yip et al. (2001) [
13] found that weight loss in the two meal replacement groups were greater (6.4% and 6.7%, resp.) compared with weight loss in the diet plan group (4.9%) although this was not significant. In addition, fasting glucose, total cholesterol, and low-density lipoprotein cholesterol levels were reduced in the meal replacement groups and the glucose change was significant compared with the diet plan group (
P = 0.01), but HbA1c was not different (0.2% difference between groups). Similarly Li et al. (2005) [
14] in a longer 12-month study found that percentage weight loss was greater in the meal replacement group (4.6%) than in diet plan group (2.3%) although BMI change was not significant (
P = 0.07). Fasting glucose was reduced in meal replacements group at 6 months and HbA1c level improved in MR at 6 months compared to the diet plan group by 0.49% (
P = 0.1 for comparison), but this difference had disappeared by 12 months (0.15%,
P = 0.6) and neither group had a significant change in HbA1c compared to baseline. Each participant in both groups received individual consultation with a registered dietitian at baseline, weeks 2, 4, 6, 8 and then monthly for the duration of the 1-year study and 77 out of 104 subjects completed the study. More subjects in meal replacements group reduced their use of medications. In a study of 119 subjects Cheskin et al. (2008) found that weight loss on a meal replacement program for 34 weeks with 1-year followup was greater than on a standard diet with more subjects 40% versus 12% achieving ≥5% weight loss [
16]. Dropout was very large with only 48 completing 34 weeks and 33 completing 86 weeks. HbA1c dropped by 0.28% in the MR group versus an increase of 0.32% in the standard diet (
P = 0.06). These HbA1c results are very similar to ours as were the changes in medication with seven more individuals reducing drugs in the MR group than in the SD group. Dosage increases were similar in both groups. In a report by Ditschuneit (2006) patients with diabetes on a meal replacement program achieved weight loss of 5.2% and 4.4% of their body weight at 6 and 12 months, respectively, [
15]. In comparison patients on a diet plan achieved weight loss of 2.9% and 2.4% at 6 and 12 months. All these studies involved a dietitian in the program delivery.
It would appear that the immediate reduction in carbohydrate using the protein-rich meal replacements was the most important cause of a fall in HbA1c at 3 months in the MR group while the 2
kg weight loss in the DB group was not large enough or had not been present for long enough to change HbA1c. The regain of some of the lost weight as well as the reduction to one MR sachet per day may be the reason for the rise in HbA1c in the MR group at 6 months and lack of difference between the 2 groups at this time point. Medication dosage reduction clearly had an effect on the results as well, particularly in the MR group. The changes in HbA1c are very comparable with the published literature. Greater weight loss is required to maintain the early changes in HbA1c.
In conclusion use of meal replacements for 6 months can increase weight loss by 2.5
kg compared with nonprofessional advice from a diet book, but HbA1c was not significantly different between the groups. In order to achieve a greater reduction in HbA1c professional advice is probably required, although this is not a guarantee of success as the Li study showed no significant effect on HbA1c at 12 months in either group despite extensive professional advice.
