Background: Since the description of superficial fascia flap harvesting, a new window of opportunity has been open in obese patients, where a higher subcutaneous thickness of tissue is present. To our knowledge, the impact of body mass index on superficial fascial flaps has not been reported. Methods: We recruited 122 patients from April 2019 to January 2020. From these patients, the 3 most common thinned flaps were selected: the superficial circumflex iliac perforator flap; the anterolateral thigh flap at the perforator A, B, and C; and the thoracodorsal flap. Two vertical measures were registered: the distance from the skin to the superficial fascia, and from this point to the deep fascia. Results: The average flap measurement presented here was within the range, as previous clinical studies. The superficial fatty layer thickness in the superficial circumflex iliac perforator and anterolateral thigh flap was somewhat similar in thickness between overweight and obese patients, showing a minimal increase with higher body mass index. The anterolateral thigh flap was found thicker among women, and no statistical difference was shown between age groups in any of the flaps. Conclusions: A better understanding of the fat layers’ thickness will result in better planning, minimizing secondary debulking procedures, decreasing operative time, and reducing general complications among obese patients. Thus, a better understanding of flap structure and physiology in obese patients will lower complications and give more predictable results.