Nutrition, the way you eat, what you eat is the major factor in your initial training results. You can safely say around 80% of those initial training results will be a direct result of your attention to your diet. The remaining 20% will come from your actual training.
The best indicator of success in your training is your clothes not your weight. Your weight may remain the same, it could even go up but if your clothes get looser then body fat is diminishing. Body fat takes up far more space than lean muscle but lean muscle is proportionately heavier.