Why Diets Do Not Work

By Lauren Neiser, MSN, APRN, PMHNP-BC

Keto. Atkins. South Beach. NutriSystem. Weight Watchers. Intermittent Fasting. Paleo. Low-Carb. The HCG Diet. Raw. Jenny Craig. Slim Fast. What do all these diets have in common? They are all ineffective and potentially harmful.

We live in a diet culture driven society that celebrates thinness and is abundant with internalized fat phobia. In the United States (US), the diet industry capitalizes on our society’s obsession with thinness, generating, in 2023 alone, $90 billion dollars in profit (Research and Markets, 2024). Within the US, there is a constant captivation and fixation related to body weight, shape, and size, “healthy” eating, and exercise. This diet driven culture keeps many individuals stuck in a yo-yo dieting cycle, often leading to malnutrition, preoccupation with food, poor body image, and potentially developing a disordered relationship with food. So, if diets are effective, why is the diet industry continually growing?

 

The short answer is diets do not work and are unsuccessful because they are often very restrictive and therefore, not sustainable.

Many diets villainize whole food groups, such as carbohydrates or sugars, which is not feasible for long term health or overall well-being.

As humans, we need a variety of foods to function, including glucose and carbohydrates, for our brains to function. Our brain solely utilizes glucose, and we cannot produce glucose ourselves, resulting in a need to obtain glucose directly from food sources (Wolrich, 2021). The best source of glucose? Carbohydrates. If we completely cut out this category of food or are following a very restrictive diet, this limits our brain’s ability to function at its highest capacity. This often leads to difficulty concentrating, inattentiveness, irritability, lower mood, heightened anxiety, fatigue or low energy levels, and poorer sleep. Another often vilified food component is fat. Fat, however, is essential to many bodily functions, including absorbing micronutrients, such as vitamin D or E, forming cells, and for overall energy (Wolrich, 2021). Therefore, if we moderately or severely limit our fat intake, we may become deficient in vitamins essential for bone health and experience weakness or lethargy. Additionally, anytime we are assigning a food item or food group a label such as “unhealthy” or “bad”, we begin to appoint morality to food. This, in turn, can lead to disordered eating. The truth is food has no morality. Food cannot be “good” or “bad”, it is simply food, a collection of nutrients. We need a vast variety of foods, including fats, sugar, carbohydrates and proteins, in order to allow our body to operate at its full capacity for overall well-being, both physically and mentally.

Research has shown that less than 10% of dieting individuals are able to keep the weight they lost off for over a year (Kraschnewski, 2010). Part of this is simply due to biology because every individual has their own set point. Set point theory suggests “that body weight is regulated at a predetermined, or preferred, level by a feedback control mechanism” within the brain (Harris, 1990, p.3310). This means your body has a weight that keeps its homeostasis or “happy place” and will adjust in any way it can to maintain the weight where it feels safest. When we engage in purposeful restriction in order to lose weight, our brains cannot recognize whether this is intentional or unintentional, leading to a starvation state. This results in our body beginning to try and conserve the energy or food nutrients it currently has. This results in a slower metabolism, changes in the way your body absorbs nutrients, and storing fat to mitigate the risk of starvation (Harris, 1990). This is the science behind why 90% of individuals who diet gain most, if not all, the weight back within one year (Research and Markets, 2024).

In the end, an individual’s weight is not simply a factor of will power. Weight stems from many different, predetermined aspects, including biological, environmental, economic, behavioral, and genetics. This is a small glimpse into why diets do not work and how they are harmful for our bodies, our minds, and our relationship with food and movement. If you are struggling with body image, disordered eating, or anxiety related to food or your body, please call the Lindner Center of Hope at 513-536-HOPE to get connected with a clinician or provider who can help.

References:

Harris, Ruth. (1990). Role of set-point theory in regulation of body weight. The FASEB Journal. 4(15), 3310-3318. https://doi.org/10.1096/fasebj.4.15.2253845

Kraschnewski JL, Boan J, Esposito J, Sherwood N, Lehman EB, Kephart DK, Sciamanna CN. (2010). Longterm weight loss maintenance in the United States. International Journal of Obesity, 34, 1644-1654. https://www.nature.com/articles/ijo201094

Research and Markets. (2024). The U.S. Weight Loss Market: 2024 Status Report & Forecast. Marketdata LLC. 

Wolrich, Joshua. (2021). Food isn’t medicine. Random House.