We fall off track because a part of us isn’t sure that the goal we’re working toward is going to make our lives better. This causes inner conflict, and when there’s inner conflict, we do the easiest thing of all: nothing. I’ve presented this simple worksheet to many clients, and I’ve found that it helps determine what’s really holding them back.

The evidence shows that this kind of behaviour change needs to happen collectively, not just individually. So we need joined-up governance at local, national and international levels. Food systems also contribute significantly to greenhouse gas emissions. This can be addressed by reducing waste or directing it back into the supply chain. A mix of different measures will be most effective. The evidence shows that taxation is one of the most effective ways to modify behaviour. Accreditation and labelling schemes can also have an impact.

Discarding classical solutions such as information campaigns, it offers a much simpler alternative: make the healthy options more tempting. How? By changing their names. Several research teams in the US have tried this strategy in various school canteens and they found that making the names “seductive”, catchy or funny can induce children to eat healthier.

In this randomized clinical trial of 602 overweight and obese adults from 40 states across the United States, gamification interventions with support, collaboration, and competition significantly increased physical activity compared with the control group during the 24-week intervention. The competition arm had the greatest increase in physical activity from baseline during the intervention; during the 12-week follow-up, physical activity was lower in all arms, but remained significantly greater in the competition arm than in the control arm.

In a meta-analysis of real-life experiments drawn from food science, nutrition, health economics, marketing and psychology, the authors find that behavioural nudges - facilitating action rather than providing knowledge or inducing feelings - can reduce daily energy intake by up to 209 kcal, the same number of calories as in 21 cubes of sugar.

“Tracking your daily activity with a pedometer, wearable, or smartphone is an important part of any physical activity program,” Patel said by email. “However, it should be combined with other behavior change strategies such as goal-setting, coaching, or social interventions to increase sustainability.”

If you want a child to eat more vegetables, it might help to use plates illustrated with pictures of vegetables.

Gamification offers advantages over other types of physical activity campaigns due to its ability to bypass the perceived barriers to becoming active. Gamified design can deliver health through stealth by encouraging people to play a fun, free game rather than take part in a fitness scheme.

Strategies for Enhancing Health in the Built Environment

Mental contrasting is essentially contrasting your happy, dream goal with your current reality, emphasizing the need for action, while implementation intentions are "if-then" statements about how you will deal with obstacles. The link goes to a journal article in which this combined technique was used to help women become more physically active, and the effect was sustained over months.