One can have an effect on the other, but how much body fat you carry is actually more important than what you weigh. You may have heard the line – muscles weigh more than fat, but that’s not correct, 1lb of fat weighs the same as 1lb of muscle. The difference is 1lb of muscle looks smaller and firmer than the fat – which takes up more room and more importantly, excess fat is bad for your health.
Losing body fat can be tricky, it takes a concerted effort to eat and exercise well consistently to see results. To lose weight you need to be in a calorie deficit, however, to lose body fat, it’s got to be the right balance of macronutrients. If you need to eat 2500 calories a day to maintain your weight then anything less will mean weight loss, 2000 calories of processed foods high in sugar will mean you lose weight – but it won’t reduce body fat and will (in the long term) badly affect your health. It’s about making the right choices.
Monitoring both body fat and weight (without being obsessive) will ensure you lose fat and find a healthy weight you can maintain. If you’ve built muscle from your exercise routine you may well look leaner but weight slightly more.
Remember that overestimating calories burned and underestimating calories eaten will hinder your results – keep a food diary. Weigh in once a week (ideally with a scale that measures bodyfat too), keep hydrated and be consistent – you’ll get there!