Among adults with DM2, we conducted a phase 2 trial to assess the effects of a 24- week 15- core session nutritional education program that focused on meal preparation training and integrated pedometer-based self-monitoring. In the 74% of participants who completed assessments, our findings demonstrate small but conclusive reductions in weight (mean weight change −2.2%; 95% CI −3.6 to −0.8) with a nearly 1- point decrease in BMI (mean change −0.9, 95% CI −1.3 to −0.4) and a net increase in step counts (mean change 869 steps/day, 95% CI, 198 to 1,540) in those who provided step count records. Although eating- out frequency did not decline, there were reductions in reported energy intake and salt consumption, as well as improvements across a range of behaviours related to the ability to control eating, and increases in time dedicated to meal preparation on weekdays. Most importantly, there was a definitive improvement in glycemic control (mean HbA1c change - 0.3%, 95% CI −0.6 to −0.1) that was not attributable to medication changes, confirming the physiological impact of the intervention. Further, there was a strong suggestion of systolic blood pressure improvement (mean change −3.5 mm Hg, 95% CI −7.8 to 0.9). We believe that these findings indicate that the intervention holds promise and merits further development and testing.
We acknowledge that the weight loss effects that we observed are less than reported in some other intervention studies. Intervention studies that have focused primarily on nondiabetic individuals have achieved a net reduction of 5% or greater in a larger proportion of participants
[6, 31–33] compared to the one fifth of our study participants. This is likely partly attributable to our focus on individuals with DM2, perhaps underscoring the particular challenge that weight loss poses to DM2 patients
Impressively, and specifically in adults with DM2, the Look AHEAD trial achieved a 5% or greater weight loss in roughly 70% of participants at one year
. The most notable difference between our strategy and that employed in Look AHEAD is the use of meal replacements in Look AHEAD
. During the first 20 weeks of the Look AHEAD intervention, participants are prescribed two meal replacements per day, one portion- controlled snack, and one self- selected meal. After 20 weeks, they are prescribed one meal replacement and two meals of self-selected foods, and use of weight- lowering medication is considered if weight loss is deemed insufficient. The use of meal replacements has been demonstrated to be an important predictor of weight loss in the Look AHEAD cohort
. However, it does potentially limit variety and flexibility in dietary intake and may therefore not be uniformly accepted, hence the need for the development of alternative strategies. Additionally, the long term feasibility of sustained used of meal replacements has not been reported; there is a very real possibility that while meal replacements may lead to greater initial weight loss, once these are discontinued, this benefit may not persist. This underscores the need for studies such as ours that endeavour to develop and test alternatives to meal replacement-based strategies.
It should also be noted that in Look AHEAD failure to complete the run- in for dietary intake and exercise was an exclusion criterion;
 we did not use a run-in period. This may also have contributed to the lesser degree of weight loss observed in our study.
In our strategy, by integrating step count self- monitoring, study participants who provided step count records achieved an 869 average increase in daily step counts, roughly one third that achieved in interventions that focus primarily on increasing walking and other step- related activity
. Given that the main focus of the intervention was on nutritional issues, the increase in step counts was notable. The step count increase was greater in those who started the intervention in fall/winter and ended in spring/summer compared to those who did the opposite (1,366 vs.436 steps/day). This is consistent with a previous observational study wherein we demonstrated that during fall/winter, step counts decline by 758 steps/day
. Thus, in the present study, those who started the intervention during the spring/summer were not only able to offset the usual fall/winter decline, they were also able to achieve a net increase. Arguably, a mean increase of at least1,000 steps/day may be needed to demonstrate definite health effects, as supported by our own observational studies
[7, 8]. Nonetheless, the 869 steps/day increase is promising, and could potentially rise to 1,000 steps/day or more with greater focus on this aspect of behavioural change.
A key finding was the demonstration of a definitive 0.3% reduction in HbA1c that was closely associated with the weight changes observed (Table
4). This reduction was determined to be unrelated to changes in antihyperglycemic agents. In terms of magnitude, it is roughly one third of the HbA1c reduction in the intensive glycemic control with metformin arm of the United Kingdom Prospective Diabetes Study (UKPDS), an arm with a 42% relative reduction in diabetes- related deaths.
 Based on UKPDS analyses, Tricco and colleagues
 recently estimated that a 0.33% HbA1c reduction may be associated with 21% fewer deaths, 14% fewer myocardial infarctions, and 37% fewer microvascular complications (retinopathy, nephropathy, neuropathy) at the population level. This estimate supports the clinical importance of the 0.3% HbA1c reduction that we observed.
Thus, even with a mean weight reduction of less than 5%, our intervention demonstrated clinically- important improvements in glycemic control. Such physiological effects of small weight changes have been demonstrated in other DM2 intervention trials, including the group that had a net weight change of 2 to 5% over a one-year period in the Look AHEAD trial
Another important signal of potential for physiological impact was the SBP reduction, although this was not definitive (95% mean change – 3.5 mm Hg, 95% CI −7.8 to 0.9), likely because of insufficient sample size. In regression analyses, however, definitive association with weight change were demonstrated: a −2.5% weight change was associated with a 3.5 mm Hg SBP reduction (95% CI −5.5 to −1.4). There was also a signal that in some individuals the increase in step counts may have contributed to blood pressure reductions; however, this was not clearly independent of weight change, and was not the primary focus of the strategy. Greater emphasis on methods to increase step counts may enhance the impact of this aspect of the intervention. For example, a recent trial suggests that encouraging stepping during television commercial breaks may importantly increase daily steps
Both participants who began the 24-week intervention in the spring/summer and those who started in the fall/winter experienced HbA1c reductions (−0.2% and −0.5%, respectively). Blood pressure– lowering was apparent for those who started in the fall/winter (SBP/DBP −8.7/-1.9 mm Hg) but those who started in the spring/summer experienced a small increase (1.2/1.5 mmHg): this must be interpreted, however, in the context of a usual fall/winter 4 mmHg SBP increase, as we have previously documented in this patient population
. Thus the intervention appears to have attenuated the usual fall/winter increase.
The main limitations of our study are related to sample size and use of a single-arm intervention rather than a randomized controlled design. We would emphasize, however, that a single- arm trial- i.e., a Phase2 trial- was deliberately pursued in order to assess for feasibility and evidence of some impact. A single-arm design permitted each participant to act as his/her own control, reducing confounding and increasing the precision of estimates. In contrast, small trials risk unbalanced treatment arms and limited scope for statistical adjustments. Another potential limitation relates to use of participant reports to estimate dietary intake and step counts. While we did detect reductions in energy intake and salt intake as well as increases in step counts (Table
3), we acknowledge that self-report of dietary intake may be subject to either over or under reporting as it relies on an individual’s memory and ability to estimate portion sizes.
 Similarly, use of step count records to monitor physical activity requires participants to reliably wear a pedometer and accurately record values. Indeed, not all of those who completed final assessments reliably provided step count records. Thus, both the estimates of dietary intake and step counts are subject to some degree of measurement error. We would emphasize, however, that the main parameters of interest in this study- changes in weight, blood pressure, and HbA1c- were all objectively-assessed.
Despite some potential limitations, the findings provide good justification for further development and ultimately testing of this innovative strategy through a large randomized controlled trial. Importantly, such a trial should be of sufficient duration to allow examination of longer term effects, adherence, and sustainability (i.e., one year and beyond). Indeed we are presently attempting to tailor a similar strategy to women with a history of gestational diabetes mellitus (Canadian Institutes of Health Research, Principal Investigator K. Dasgupta, CAI 117789); this younger patient population at risk for DM2 may be able to achieve greater changes in weight and step counts, potentially translating into even greater vascular health improvements. Further, contingent on focus group discussions, we are considering the implementation of a tapering course of meal replacements concurrent with the acquisition of meal preparation skills. This could diminish long term reliance on meal replacement products, while allowing initial benefit from their use.
In this study, the average cost per participant per session (and covered through the study) was roughly $50 CDN (room rental, chef, groceries, dietitian), with a 15- session program costing approximately $750.00 CDN per participant. In an actual program, such a fee could be prohibitively high for some persons with DM2, given the higher prevalence of DM2 in more disadvantaged populations
. Translating such a strategy into a sustainable program will thus require important cooperation/contributions from key stakeholders (diabetes associations, local businesses, government agencies). While sessions were held at kitchen workshops of a grocery chain, other options would include kitchens at schools and community centres.
The findings reported in this study provide evidence to support the merits of a group-based dietary education strategy that is centered on preparing a meal, eating it together, and discussing both optimal eating habits and the challenges of adopting these. In individuals followed for DM2, the strategy tested demonstrated reductions in weight as well as effects on glycemic and blood pressure control- even in the context of medication therapy. There is a need to further develop and target the intervention to achieve a greater magnitude of effect. Nonetheless, our findings support the merit of this line of enquiry. The prevention of overweight- related complications requires a range of creative management options, allowing a ‘fit’ between patient and approach. Our strategy may emerge as one such option, empowering overweight persons with or at- risk for DM2 with the tools to develop a healthy relationship with food and better physical activity habits in the modern obesogenic environment.