Secret of weight loss? It’s all in the planning

PLAN fasting days in advance. Make sure you increase your water intake, as you miss out on the fluids in your usual food and you lose water when you burn fat. Aim for 2-3 litres a day.

SOUPS are satiating, cheap and practical. You can take them to work for lunch and keep portions in the freezer. Go for the non-starchy vegetable or clear broths such as miso soup.

HOT drinks suppress appetite, so teas and coffees — ideally black with no sugar — are great.

USE flavour enhancers so meals are as tasty as possible. For example, lemon, pepper, chilli, garlic, gherkins, mustard and herbs all add few calories.

EXPECT side-effects such as tiredness, lightheadedness and headaches ( often related to dehydration); hunger (it comes in waves and passes so try to ‘surf the wave’); and feeling colder. All should settle over a week or so and are usually less noticeable if you raise the proportion of fat in your diet — try recipes that include avocado or oily fish.

AVOID fasting or discuss with your doctor first if: your BMI is below 20, you have a history of eating disorders, are under 18, on medication, are pregnant or breastfeeding, have a significant psychiatric disorder, are unwell or have a significant medical condition, are recovering from surgery, are frail or have other medical conditions.

THE first few weeks can be tough, but your body adapts. Your appetite settles. Most people feel better and find they have more energy and a clearer head. It helps to get support. Website thebloodsugardiet.com has useful resources and a supportive community.