Yeah you're getting downvoted because you started with this.  Food journaling is nearly pointless  I agree with the 3 lengthy paragraphs after this sentence, but food journaling is not pointless. Yes, the margin of error is quite large. That doesn't make it pointless. It just means you have to do exactly what you said - consistently stay well below your tdee. If you lose weight faster than you want, add 100cal or so and keep going. And vica versa. Random error will smooth itself out over time, and consistent bias error will expose itself in your first 2 weeks of counting. Just adjust and keep going.