Work out how many calories you burn a day on average and eat this many (to maintain weight) or 20% less (to reduce weight)
Swap one of your sugary snacks with a healthier replacement (e.g. a piece of fruit) each day. And yes I know fruit has some sugar in it but a banana over a Mars Bar will help you cut calories and provide less of a post sugar slump.
Stop having cheat meals. Cheat meals create a restriction / binge / food as a reward mindset. Eat whatever you want whenever you want within reason without viewing food as good and bad.
Eat protein. Aim to eat 1g of protein per kg of body weight. Will help you feel satisfied without overeating.
Drink at least 0.033 litres water per kg of your body weight each day (so if you weight 60kg drink two litres a day). Fat loss, performance – hydration is so important to your health.
Don’t exercise at all at the moment? Aim to complete a 30 minute session every week for a month, two 30 minutes sessions a week the next month and three 30 minutes sessions the following month. Boom = Exercise habit created.
Increase your NEAT. However much you exercise aim to increase your non exercise movement by at least 10% each day (i.e. walk more)
Get more sleep. Enough sleep every night will help with weight loss, stress, energy levels.
Learn something new. Want to learn to do a handstand, swim, play netball? Practicing towards mastering a skill will get you moving without exercise being the main goal itself.
Set yourself a challenge. Run in a race, do a Tough Mudder, compete in a swimathon. Setting a challenge can give you the incentive to get to your training sessions and maintain focus.