Can taking flaxseed oil make yu put on weight?

Yes: It's a popular cooking oil and like anything else greasy and good-tasting, we tend to overeat and get fat from it. If you're actually taking the oil, it's still calories. Real evidence of any health benefit remains sparse at best. Why not just eat sensibly, avoid unhealthy habits, and focus on physical fitness? Health doesn't come from a bottle or pills. Best wishes.