Yes, I have been there before. You're not absorbing nutrients properly. The same with someone overweight, similar problem but just a different outcome. Imbalance basically. Unhealthy lifestyle or unhealthy person or both.
I have been in both situations. I have been bloated and overweight, or underweight. I have found in either situation that I simply needed to forget my weight situation and start concentrating on building my health (gut).
This meant completely eliminating Sugar
in all forms (sugar, fruit, honey, milk), grains (due to their high carbs, gluten, etc) and concentrating on protein in eggs and meat, plenty of vegetables, plenty of healthy fats that aid healing and tissue repair (bile flow also).
Once you do these things and stick at it, the gut can often begin to heal over time and the body can begin to absorb nutrients again, and weight usually balances itself automatically. However, for some who are underweight, they can really get upset when they first go on this diet and found they get even MORE underweight, but do not realise it is mostly temporary and their soul thought should be building their health up.
OFten a person with this problem may have a high yeast overgrowth, so they lack the nutrients for health or normal weight. If you go on the diet, over time you should improve. The body simply needs a proper diet in order to heal. If that is not done, you may find yourself going in circles trying all sorts of expensive "promises" from advertisers. If you build a proper foundation for your health? Your body will thank you for it later.
It does take time, sometimes weeks to see results or longer. Main thing is not to concentrate or worry about your weight, but instead focus on health and healing foods and fats.
Here is an excellent website for gaining information on what to eat and what to avoid
It is for those suffering candida, and those who just want to get healthier, or for any illnesses at all.
If you wish to learn more about the health benefits of proper fats? and why they are necessary? Read this link here.
I think both these websites are brilliant in their information and exposing many of the new age lies/myths spread today about diet and fats. The idea of no fat or low fat being healthy is actually very harmful. The body requires fats (the right kind) for many functions.