I think you just confused yourself with a number of unproven hypotheses:
1) That the conservation of mass applies simply (mass of food in = mass of food stored as fat) rather than considering that some of the food is stored otherwise, some is converted to other bodily materials and some is excreted
2) Body fat (ie triglycerides) and olive oil (mostly oleic acid but also containing other fatty acids) are different, so obviously there are metabolic processes providing conversion. Indeed there must be such processes to convert carbohydrates to triglycerides otherwise you'd not be able to argue that carbs can increase body fat
3) You've ignored the fact that what you eat influences your metabolism, particularly your ability to use freely available and stored fats
Try walking first
Four years Primal with influences from Jaminet & Shanahan and a focus on being anti-inflammatory. Using Primal to treat CVD and prevent stents from blocking free of drugs.
Eat creatures nose-to-tail (animal, fowl, fish, crustacea, molluscs), a large variety of vegetables (raw, cooked and fermented, including safe starches), dairy (cheese & yoghurt), occasional fruit, cocoa, turmeric & red wine