What are your thoughts on lchf diet and why have doctors not made the link between the consumption of grains (as an example) and increase in weight?

A fad diet: You weight gain or loss reflects the balance of caloric intake vs. calories spent. Eat a balanced diet, exercise, if you want to lose weight, reduce your intake of food, Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.