For any weight-based goal, the dietary adjustment we need to consider most of all is tempering our calorie intake based on our new energy expenditure. The calories we harvest from the foods and fluids we ingest are used to produce energy. Or, when our energy needs are met, calories are stored in our blood stream, muscles, fat tissue and so on. Once energy is produced and used, it is lost. It cannot generally be recycled.
The quickest way to adjust our food intake based on our activity to work out our basal metabolic rate (BMR) (i.e. how much energy we burn at rest) and then multiply it based on how our activity level has changed. One rough way to calculate your BMR is to multiply your bodyweight in kilograms by 22 for men, and 20 for women. Next, you multiply your answer by one of the following activity multipliers to get your daily maintenance calorie needs:
Multiply by 1.0-1.2 if you are now sedentary
Multiply by 1.3-1.4 if you are now lightly active
Multiply by 1.5-1.6 if you are now moderately active
Multiply by 1.6-1.7 if you are now very active
Multiply by 1.8-1.9 if you are now extremely active
Being ‘moderately active’ generally means you are doing 10,000 steps a day, and three 90 120 minute weightlifting sessions a week. Keep in mind that these estimates are based on population averages, and the rough BMR calculation works best for people with average weights and fat percentages. That being said, this calculation should give you a general idea of how much you need to consume to stay on top of your weight.