One common reason is insufficient training frequency. Training only a few times a week may be too little for significant changes, as the body adapts to the same load over time and stops progressing.
Additionally, inadequate protein intake can slow progress, as proteins play an important role in preserving muscle mass and also in the feeling of fullness during a calorie deficit.
The problem may also lie in the training method itself. Focusing solely on light exercises or a high number of repetitions without basic, complex exercises often does not yield desired results, as greater muscle mass contributes to higher energy expenditure.
Moreover, excessive cardio training can lead to fatigue and increased appetite, making it difficult to maintain balance in diet and training. The key is moderation and combining different types of training.
Another mistake can be overly restrictive diets, where total calorie intake is reduced due to excessive limitations. Such an approach can slow metabolism and make long-term maintenance of results more challenging.
For progress, the most important factor is the balance between training, diet, and rest, as small changes in habits can have a significant impact on outcomes.