Sarah Faigle, MPH, RD, LDN

2020 has brought many new challenges to our daily lives, but one thing that has not changed with the COVID-19 pandemic is – DIET CULTURE! Diet culture tends to assign moral judgements to foods, body sizes and shapes, and equates weight loss and thinness with “health.” For some Americans, increased time at home and on the computer during the pandemic may contribute to investigation of popular diets. Even if you do your best to avoid diet culture, it is difficult to avoid hearing some mention of ketogenic diet or intermittent fasting. So, what is it all about?

The ketogenic diet was first developed as a nutrition therapy for children with seizure disorders. It has also been considered as a therapy for other neurogenic disorders such as Alzheimer’s and Parkinson’s disease. The ketogenic diet is a very low carbohydrate diet, in some ways a “stricter” version of the popular Atkin’s diet. By restricting carbohydrates, the body is forced to use fat as a source of energy, this process results in the production of “ketone” bodies. Our ability to extract energy from fat as opposed to only glucose is an important and adaptive part of our physiology; however, forcing our bodies to do this long-term is likely unhealthy. The ketogenic diet is low in fruits and vegetables, fiber, and whole grains—foods that are important for a balanced diet. Some of the reported negative side effects are irritability, constipation, and micronutrient deficiencies. In addition, this diet often includes high levels of saturated fat, processed meat content, and cholesterol. Given the restrictive nature of this diet, many individuals are unable to sustain it long term.

Intermittent fasting is a popular diet trend that takes many forms. Intermittent fasting may include restricting intake on some days of the week, restricting intake to every other day of the week, or restricting intake to 8-12-hour periods per day. While intermittent fasting does not restrict any specific types of food, it does limit the time you have to get adequate nutrition. The schedule limitations can negatively affect overall nutrition and also seriously interfere with one’s social life and the ability to join in family meals. Although there is some benefit to having times in the day when we are not eating, there is no evidence that our bodies require more than an overnight fast to promote health. If you sleep on average eight hours per night, that typically amounts to an extended period of time when you are not eating. What most of us actually need is improved sleep hygiene, not intermittent fasting.

So if restrictive, fad diets have limited long-term benefit, why are they so popular? A main contributing factor is the diet industry. The diet industry is estimated to be worth $72 billion (that’s Billion with a B), and it is in their best interest to market new diets regularly and promise great results. The truth is most diets only lead to weight loss for a few weeks and are not sustainable. The average dieter gains the lost weight back within a year of starting a diet. It is important to note that some diets (like the ketogenic diet) have shown positive health benefits for specific populations with specific health conditions. They were not designed to be hijacked by the diet industry for weight loss purposes. In addition, the health benefits are not maintained if the diet is not continued. Cycling between different types of diets and exposing your body (and mind) to repeat cycles of dieting, weight loss, and weight re-gain can be harmful both physically and psychologically.

Restricting one’s intake can have a significant impact on mood and contribute to feelings of deprivation and failure. For individuals with eating disorders, dieting has several negative effects. Restriction via ketogenic diet, intermittent fasting, or other means can worsen malnutrition in patients with anorexia nervosa and can trigger an increase in binge eating in patients with bulimia nervosa and binge-eating disorder. In addition, diets that cut out whole food groups or limit one’s intake to a short window each day are very likely to contribute to nutrient deficiencies over time.

A healthy alternative to trendy diets is the tried and true pattern of eating regularly and selecting foods from a variety of food groups. We know a diet high in vegetables, fruit, whole grains, and a variety of fat and protein sources is healthful for most individuals. We also know that good sleep hygiene is positive for physical and mental health, weight management, regulation of hunger cues, and provides a natural fasting period (hence the name “break-fast”).  We know that the ability to eat with family and friends is good for our physical and emotional health. This type of eating does not come with catchy slogans or short term promises, but does offer a long term, sustainable way to promote our own wellness.