N2 nicotinic receptors are found in the brain, plus the autonomic and parasympathetic nervous systems [1]. Different subunits make up these two types of nicotinic receptor, which is why we consider them separately. Muscarinic receptors have a different mechanism of action.
Your body weight can regularly fluctuate, but the persistent, unintentional loss of more than 5% of your weight over 6 to 12 months is usually a cause for concern. You should pay particular attention if you experience other symptoms, such as tiredness, loss of appetite and a change in your toilet habits.
For example, a diet deficient in calories is out of balance and can cause you to become underweight. But eating a diet with more calories than you burn in a day will lead to weight gain. An unbalanced diet can also contain more of certain food groups than others or may lack certain food groups or nutrients.