By: @drmelissa.co

‘Restrictive diet’ is an umbrella term that encompasses changes to how, when and what one eats. To some, avoiding junk food is considered restrictive; to others, a restrictive diet may be as extreme as consuming food from only one food group or strictly avoiding others.

Regardless, the ultimate question is, when do restrictive diets help and when do they harm?

There are many medical scenarios that require changes to diet for the sake of ameliorating symptoms, promoting healing, and preventing disease long-term. For example, those suffering from celiac disease and/or other autoimmune disease greatly benefit from the removal of gluten from the diet; this may be required as a temporary or long-term solution, depending on the patient. The reduction and/or elimination of dairy may help in the healing of certain skin conditions. Again, this may be a short or long-term component of a patient’s treatment plan. Someone who suffers from chronic infections could be greatly improved with the elimination of all processed sugar, allowing only for whole fruits, until this condition improves. In the case of insulin resistance or Diabetes, processed sugars and flours are worth reducing, if not eliminating. Typically these changes to diet are accompanied by other lifestyle modifications as well as medical interventions (including supplementation, acupuncture, and possibly pharmaceutical care). The more holistic the treatment, typically the better the result from the dietary changes.

Certain changes to diet can also improve quality and length of life overall. In the research, the Mediterranean diet is consistently as ranked one of the best diets to promote health in general while decreasing risk of disease and death. I would not consider this diet restrictive per se, but rather one that advocates for a balanced approach to eating and lifestyle. It encourages nutritional variety, with an abundance of fresh fruits and vegetables, and provides guidance around serving frequency and type of healthy fats, proteins, whole grains and dairy products. Home-cooked meals are preferred, and eating in community is suggested. This diet supports a healthy microbiome and digestion, mental health, immunity — all of which lead to better health now and for years to come. 

There are many scenarios where drastic changes to diet may temporarily improve symptoms (like low energy or bloating) or assist someone in reaching certain goals (for example, weight loss), while causing dysfunction long-term. The more restrictive the diet, the more likely the long-term problems.

Restrictive diets can pose a few major risks. Firstly, a restrictive diet may be lacking the essential nutrients to support health overall. For example, a vegan diet typically requires supplementation of vitamin B12, iron, omega-3 fatty acids, protein, among other nutrients. A ketogenic diet will require supplementation with fibre, pre- and probiotics, and likely a variety of vitamins and minerals found in fruits and vegetables that may be avoided. 

In the long-term, nutritional deficiencies can lead to major health concerns and chronic illness. Certain concerns I see in practice that can relate to nutritional deficiencies resulting from restrictive diets include: digestive disturbance, changes to a woman’s period, concerns around fertility, autoimmunity, issues with sleep, skin issues, mental health concerns like anxiety or low mood, chronic infections, pain, fatigue, weight gain and the resultant diseases. Symptoms of nutritional deficiencies often take time to present; months or years may pass before these issues become apparent.

Another potential risk that comes with restrictive diets is a change to metabolic health. Some restrictive diets lead to over- or under-consumption of calories which may lead to challenges around appetite, energy, and weight. Blood sugar imbalance and undesirable changes to metabolism can occur if we engage in restrictive fasting patterns without the proper support, leading to a host of issues including brain fog, digestive disturbance, sleep concerns, and issues with energy. Steady blood sugar requires certain nutrients to be eaten in optimal ratios at ideal times of day. Long-term, diets that rely on fasting can lead to appetite dysregulation and binge-restrict cycles that may lead to weight gain and other major concerns over time.

Stress and social isolation may also be a risk, along with the potential to cause or worsen disordered eating. To adhere to a strict diet of any kind can be a source of mental anguish. It may be challenging to find or create recipes and grocery shop appropriately. Fears around food may be caused or exacerbated, and relationship with food can become increasingly dysfunctional. Social situations may also become challenging, and some individuals may avoid them in order to avoid the temptation of eating outside restrictive dietary guidelines. 

So, do restrictive diets help or harm? The answer, like most things related to health, is: it depends. If the changes made are done for health reasons and under supervision, they can be helpful. If not, it is hard to say.

Information around health and wellness is more accessible than ever, and fad diets claiming great results intrigue individuals to make major changes to eating habits without medical guidance. At times, these restrictive diets may lead an individual to feel great initially, supporting the belief that the changes made are healthy. Despite this initial improvement, I recommend avoiding restrictive diets unless otherwise advised by your Family or Naturopathic Doctor.

Seeking the assistance of a licensed medical provider who is up-to-date with current nutritional and medical research is invaluable. It is important to be thoroughly assessed, mentally and physically, with a case history and appropriate testing to discern what your unique nutritional needs are. I recommend finding a practitioner you can continue care with so that your health status can be regularly monitored either quarterly, biannually, or annually to ensure you are meeting your nutritional needs, and the diet can be tweaked accordingly based on your age and stage in life.