Ever wondered why you feel hungry or full? There are a number of systems that work together to tell you when to seek out food, with the key players being Leptin and Ghrelin.

Our fat cells produce leptin, which regulates food intake and energy expenditure. Leptin levels correlate with your fat mass; if your fat mass is lower than your genetics would like it to be, the brain will sense the lower leptin levels and stimulate your hunger. In women, low leptin levels will also mean reduced fertility and/or amenorrhoea (lack of periods). The rationale for this is: if your body is low in energy stores, it’s not safe to start growing a baby!

It doesn’t only matter how much ‘padding’ we have, but also the pattern of our eating. Our gut cells release a hormone called Ghrelin in response to lack of protein in our diets or irregular meals. Ghrelin has a direct impact on the hormones that regulate our menstrual cycles (talking to the ladies here): it suppresses the luteinising and follicle stimulating hormones, which in turn impairs follicle maturation and ovulation..

Being ‘within the healthy BMI’ range does not necessarily mean that your body will be ‘ready’ to have a baby. You need to be at a weight that is genetically set for you as ‘healthy’ and eat regular, and balanced meals. Other factors that are important include exercise (not too much!) and avoidance of too much stress. The latter two increase cortisol levels, which also tends to suppress those all important menstrual cycle hormones…