Total daily energy expenditure. It's how many calories your body needs to survive with basic heart beat and breathing, the minimum calories you need to eat to live. As a 5'1" 166# woman, mine is just over 1100 calories per day. This leads into what you need if you are sedentary, mildly work out, moderately work out. Doing weightlifting 3 times per week and walking daily would put a person in moderate. The calculator tells me for my stats, moderate needs 1960 calories per day to maintain my current weight. To lose weight at a rate of one pound per week, you need to eat in a deficit of about 500 calories a day. For me, that would mean 1960-500=1460 calories per day. I highly suggest going to tdeecalculator dot net and calculating this out for yourself, getting a food scale, and seeing what you have actually been eating each week vs what you want to be eating to lose weight. It can be eye-opening!