The Cochrane Collaboration found that exercising alone led to limited weight loss. In combination with diet, however, it resulted in a 1 kilogram weight loss over dieting alone. A 1.5 kilograms (3.3 pounds) loss was observed with a greater degree of exercise.[29] Even though exercise as carried out in the general population has only modest effects, a dose response curve is found and very intense exercise can lead to substantial weight loss. During 20 weeks of basic military training with no dietary restriction, obese military recruits lost 12.5 kg (28 lb).[30] High levels of physical activity seem to be necessary to maintain weight loss.[31] A pedometer appears useful for motivation. Over an average of 18-weeks of use, physical activity increased by 27% resulting in a 0.38 decrease in BMI.[32]
https://en.wikipedia.org/wiki/Management_of_obesity#Exercise
[29-32] endnotes in Wikipedia
Also interesting, a meta-analysis:
Effects of Different Exercises Combined with Different Dietary Interventions on Body Composition: A Systematic Review and Network Meta-Analysis
Yongchao Xie, Yu Gu, Zhen Li, Bingchen He, Lei Zhang