As a registered dietitian specializing in both eating disorders and gastrointestinal health, I understand the physical and psychological challenges my clients endure when changing their eating behaviors from restrictive to more inclusive. Quite often after a long-term period of food restriction, or starvation, the process of starting to eat more again can be accompanied by uncomfortable digestive symptoms such as extreme fullness, bloating, constipation and/or diarrhea, heartburn, etc. Why is this? Well, there are several reasons we will explore.
In the case of chronic energy restriction, the muscles that line our digestive tract can weaken from less use and reduced energy supply. Upon starting to eat more food, this process is not immediately resolved, much like how it took some time to degrade, and during this time individuals may experience extreme fullness, nausea, bloating, reflux, or more for up to several weeks to several months. Unfortunately, this is often a big barrier, both physically and mentally, to continuing these positive changes of increasing food and may be interpreted as “I must be eating too much”. However, when these digestive difficulties were a direct result of inadequate eating, they can only be resolved by continuing to eat to restore the body’s nutritional status.
Another potential change, specific to an often-seen protein deficiency in the diet, is how our body can break down, absorb and transport nutrients in the digestive tract. This is because enzymes that break down larger molecules into smaller molecules, transporters that carry nutrients through the intestine to deliver throughout the body, and hormones that help signal these processes to occur, are all derived from proteins. In some situations, individuals may become newly lactose intolerant, be unable to digest/tolerate higher fat foods or just feel like no food is agreeing with them and like they need to resort back to “safe foods”. It’s important to evaluate when the food intolerances started, such as since the eating disorder became more restrictive versus if they pre-dated the eating disorder as you work on challenging more foods. Things like digestive enzymes can be of help during this restoration phase and oftentimes are only needed temporarily until the nutritional restoration has been completed.
Finally, another disruption in the digestive function that may occur as a result of disordered eating habits is that of our migrating motor complex or MMC. The MMC is the system that coordinates muscle movements, and peristalsis, in our GI tract. This system can be impacted by eating behaviors such as too long of periods of time in between eating, for example, only eating one or two times per day, or conversely, too frequent of eating, such as grazing every hour on small amounts of food. The MMC works in cyclical phases and is paused by the presence of eating. Therefore, not allowing enough time between each phase (at least 2 ½-3 hours) or allowing too much time (5+ hours) between eating can throw the rhythm off and cause people to experience symptoms such as extreme bloating, constipation, reflux, etc after eating. This may be interpreted as “I need to eat less” or “most foods don’t agree with me”. In fact, however, it is evidence of the importance of establishing a consistent eating schedule every 3-4 hours throughout the day, much like the importance of establishing a consistent sleep schedule for your circadian rhythm.
While the focus of this blog was reviewing the effects of eating disorders/disordered eating behaviors on our digestive function, what about when the GI condition pre-dated and possibly led to the formation of negative eating behaviors? In my next blog, I will explore this alternate side!