Weight loss lifestyle modification programmes recommend a low-fat, (relatively) high-carbohydrate, low-calorie diet aimed at inducing a calorie deficit of 500–1,000 kcal/day. This should produce a mean weight loss of 0.5–1.0 kg/week and eventually reduce cardiovascular risk markers [6]. Unfortunately, the main obstacle to reaching these goals is the patients themselves, and adherence is often an issue. However, empowering patients by training them to count their own calorie intake, with the aid of a purpose-designed booklet, can go some way to improving adherence, as can increasing dietary structuralization and limiting food choices. Providing comprehensive meal plans, including grocery lists, menus, and recipes, helps to add structure to the diet, and restricting the choice of food will reduce temptation and the opportunity to miscalculate energy intake [4]. The effectiveness of this strategy is supported by a study showing that the provision of both low-calorie food (free of charge or subsidized) and structured meal plans resulted in significantly greater weight loss than a diet with no additional structuralization [7]. Another useful strategy for increasing diet adherence is meal replacement, as confirmed by a meta-analysis of six RCTs, which showed that patients given liquid meal replacements lost 3 kg more on average than those on a conventional diet [8]. Finally, a similarly effective strategy for facilitating dietary adherence and weight loss is the use of portion-controlled servings of conventional foods [9].

The goal of lifestyle modification programmes is to help patients gradually achieve a level of physical activity sufficient to produce a calorie deficit of at least 400 kcal/day [10]. Patients are encouraged to check their baseline number of steps using a pedometer and then to add 500 steps at 3-day intervals up to a target value of 10,000–12,000 steps/day. Jogging (20–40 min/day), cycling, or swimming (45–60 min/day) may replace walking. Unlike diet adherence, exercise adherence tends to increase the less structure is imposed, presumably through a reduction in the barriers to exercising (e.g. lack of time or financial resources) [4]. This is supported by several studies, for example, one showing that patients tend to engage in more physical activity if instructed to do so on their own at home than if asked to attend on-site, supervised, group-based exercise sessions [11]. Interestingly, it has also been reported that increasing lifestyle activity (e.g. using stairs rather than elevators, walking rather than riding the bus or driving, and reducing the use of labour-saving devices) can produce comparable weight loss to structured exercise programmes, but greater weight maintenance over time [12]. It may also be helpful to suggest multiple short sessions of exercise (of 10 min each), as opposed to long workouts, an approach that seems to help patients accumulate more minutes of daily exercise [13].

The cognitive behavioural therapy component of lifestyle modification programmes is based upon a set of procedures, which have been described in several recent reviews [4, 5, 14], aimed at addressing both weight loss and weight maintenance obstacles (see Table 27.1).

One of the main problems with traditional weight loss lifestyle modification programmes delivered in group sessions is that they are essentially a series of pre-packaged lessons in which the clinicians teach all patients all the procedures involved in the programme. The lessons are delivered in the preplanned order, even if one or more patients have not yet had enough input to overcome their problems or have failed to understand entirely. These programmes therefore more resemble psycho-educational intervention than the cognitive behaviour therapy applied in the treatment of other psychological disorders, in which the approach is highly personalized and the procedures are introduced in such a way as to target the specific processes maintaining a patient’s problems. The most recent developments in weight loss lifestyle modification programmes partly have made some steps to personalize delivery by introducing individual sessions with a case manager [15, 16], but the set lessons and uniformity of procedures still apply.

The Villa Garda lifestyle modification programme [5], on the other hand, has been designed to maximize the individualization of such treatment and is delivered in individual sessions that follow a structure similar to that of cognitive behavioural therapy for eating disorders (i.e. in-session weighing, reviewing self-monitoring, setting the agenda collaboratively, working through the agenda, setting homework, summarizing the session, and arranging the next appointment). The programme also benefits from the introduction of the personal ‘cognitive behavioural formulation’, a procedural tool specifically designed to further individualize the treatment. The formulation, widely used in other areas of cognitive behavioural therapy [17], but not in standard weight loss lifestyle modification programmes, is a visual representation (a diagram) of the main cognitive behavioural processes that are hindering adhesion to weight loss and lifestyle change in a particular patient. Led by the clinician, but with the active involvement of the patient, the formulation is constructed step by step, without haste. A natural first step in this process is to elicit from the patient which, if any, stimuli are associated with eating (i.e. the sight of food, social eating situations) and/or do not (i.e. life events and changes of mood) influence their eating behaviour. The clinician can then assess whether overeating is maintained by any positive emotional and/or physical consequences of food intake and/or bring to light any problematic thoughts (see Fig. 27.2). In this way the formulation helps the clinician to select the specific procedures most likely to help the patient and to implement a targeted, fully individualized treatment. Once the formulation has been drawn up, the clinician can discuss its implications with the patient, emphasizing that control of eating is not wholly dependent on their willpower, but can be improved through specific strategies designed to counteract the processes hampering adhesion to the eating changes necessary to lose weight. The clinician should also stress that the formulation is provisional and will be custom modified as needed during the course of the treatment.

A recent systematic review on the outcome of weight loss lifestyle modification programmes found that at 1 year, about 30 % of participants had a weight loss of ≥10 %, 25 % of between 5 % and 9.9 %, and 40 % of ≤4.9 % [18]. As mentioned, weight loss reaches its peak after 6 months of treatment, and in the absence of a weight maintenance programme, the trend starts to reverse, with half of patients returning to their original weight after about 5 years [19]. However, trials of the latest incarnations of weight loss lifestyle modification programmes that include the most innovative and powerful procedures have shown better long-term results. The most striking example is the Look AHEAD (Action for Health in Diabetes) study, which assessed the effects of intentional weight loss on cardiovascular morbidity and mortality in 5,145 overweight/obese adults with type 2 diabetes, randomly assigned to intensive lifestyle intervention (ILI) or usual care (i.e. diabetes support and education – DSE). At year 8, 88 % of both groups completed an outcomes assessment, which revealed that ILI and DSE participants lost, on average, 4.7 % and 2.1 % of their initial weight, respectively (P < 0.001). Among the ILI and DSE participants, 50.3 and 35.7 %, respectively, lost ≥5 % (P < 0.001), and 26.9 and 17.2 %, respectively, lost ≥10 % (P < 0.001) [20]. These impressive figures show that well-conducted lifestyle modification programmes can produce clinically meaningful weight loss long-term.