There is often a controversy regarding what kind of diet is best for weight loss. People often have the misconception that one or the other diet is better for weight loss. The reality is that none of the diets is a perfect diet but rather a healthy and balanced diet incorporating a variety of foods is best for maintaining an ideal weight.
The diet required for a person for maintaining a healthy weight depends upon many factors which can vary with time. The most important of these are the age, gender, level of physical activity and medical conditions of the person.
As a person ages, the metabolism slows down gradually and the caloric requirement decreases. So, the caloric requirement for a 40 year old individual would be automatically less than that for a 20 year old. Males usually have a higher metabolic rate as compared to females and would require more calories. Females tend to have higher caloric requirement during pregnancy and lactation but this would decrease once they have stopped breast feeding because of the metabolic slowdown.
The level of physical activity of an individual plays a great role in the caloric requirement. Physical work, exercise and sports not only burn calories directly but also boost the metabolic rate and hence lead to more caloric expenditure at rest. This leads to a manifold increase in caloric requirement and for high performance athletes can go upto 10000 calories per day.
There are numerous medical conditions which can also affect the caloric requirement and mandate certain dietary restrictions. Diabetic patients for example, are required to take less of simple sugars and carbohydrates to avoid fluctuations in their blood sugar levels. Patients with hypothyroidism often have slow metabolism and are required to take less calories to avoid weight gain. Patients with chronic renal disease may be advised to take less salt and those with liver or pancreatic insufficiency are put on a low protein diet.
So, in a nutshell, no diet is perfect and has to be tailored according to the person and the internal and external factors which change the dietary requirements.