Of course calorie deficit makes you lose weight. And of course adding extra calories makes you gain weight.
Olive oil helps you lose weight if you reduce other types of fats and use olive oil instead.
If you wish to read further into this, here's a few good publications on it:
Razquin C, Martínez JA, Martinez-Gonzalez MA, et al. A 3 years follow-up of a Mediterranean diet rich in virgin olive oil is associated with high plasma antioxidant capacity and reduced body weight gain. Eur J Clin Nutr. 2009 ;63:1387-93.
Álvarez-Pérez J, Sánchez-Villegas A, Díaz-Benítez EM, et al. Influence of a Mediterranean Dietary Pattern on Body Fat Distribution: Results of the PREDIMED-Canarias Intervention Randomized Trial. >J Am Coll Nutr 2016
Mozaffarian D. Food and weight gain: time to end our fear of fat. Lancet Diab Endocrinol 2016
Estruch R, Martínez-González MA, Corella D, et al. Effect of a high-fat Mediterranean diet on bodyweight and waist circumference: a prespecified secondary outcomes analysis of the PREDIMED randomised controlled trial doi:10.1016/S2213-8587(16)30085-7