What Causes Back Fat Take a look at your activity level. I work a full-time job where I sit for 40 hours per week and have done this for 29 years. Diet Processed foods with additives and preservatives, fast-food, and junk food are high in fat, sugar, and calories. This can lead to back fat. I am 58 years, postmenopausal, dealing with some stressful days and I love carbs. Most recently I have dev[...]