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Why Diets Don't Work

By 2019, the diet industry was worth a whopping $72 billion (1). Each year, nearly 45 million Americans go on a diet and an estimated $33 billion is spent on weight loss products (2). Although this is true, you may have heard some buzz about diets not being as life-changing as they are often promised to be. On the other hand, you may have experienced the failures of dieting on a personal level. If this is the case, I want to point out that this was a failure of the diet, not of you or your lack of willpower like the diet industry would like us to believe.

As a non-diet dietitian, I am well aware that dieting doesn't work. It seems that more people are coming to the collective realization that dieting doesn't work. Yet, why does dieting remain so popular? The answer to that lies within the huge diet industry that wants us to keep believing in diets so they can make a profit. It's important to note that the dieting I am referring to includes weight loss diets and fad diets that are often adopted to meet societal standards. Following a specific diet due to a medical necessity is encouraged if recommended by your healthcare provider. A registered dietitian can help you navigate adopting such a diet in a way that fits your lifestyle and needs.

In this article, I will discuss why diets don't work and how we can shift our focus to forming habits that lead to long-term health and well-being.

The "success" achieved through dieting is often short term

A study published earlier this year in The BMJ looked at the effectiveness of several popular diets for weight loss and cardiovascular health. This study reviewed 121 randomized trials, which included close to 22,000 patients in total. Their findings revealed that, on average, the diets reviewed resulted in modest weight loss and considerable improvements to cardiovascular health after 6 months, but after 12 months, those effects largely disappeared (3).

A similar study that was published in 2018 discussed the previous analysis of 29 long-term weight loss studies. Across these studies, they found that within 2 years, more than half of the lost weight was regained. Within 5 years, more than 80% of the lost weight was regained (4).

These are just 2 of the many studies that suggest that any weight lost from popular weight loss diets is often short-term, and that eventual weight regain is very common after this sort of intervention.

The body often goes into "survival mode" when put on a diet

Many weight loss diets promote a very low daily calorie intake. With that being said, the body cannot tell the difference between a fad diet and starvation. If someone consumes an average daily calorie intake below what their body needs for basic function and survival, then the body adjusts via several hormonal and metabolic changes.

For example, as the body receives fewer calories than it needs for survival, it's metabolic rate adjusts in order to preserve as much energy in our adipose (fat) tissue as it can, which can lead to weight gain or stability overtime, despite any effort to lose weight via low-calorie diets. This is because the body works hard to maintain a weight that it can function optimally at.

In addition, our hormones are affected when we diet. As you consume less energy, the body increases production and release of our hunger hormone, ghrelin, which works to increase food intake. With chronic dieting and the loss of adipose tissue, your body produces less of a different hormone, leptin, which is produced by fat cells and works to inhibit hunger.

The result? You are left with an altered metabolic rate, increased hunger and a decreased ability to feel full, leaving you feeling less satisfied after eating and increasing your risk of eating more than your body needs. This can lead to eventual weight regain or maintenance, despite the original intent of losing weight.

Dieting can have harmful psychological effects

You may or may not be familiar with the well-known Minnesota Starvation Experiment, which was performed at The University of Minnesota during World War II under the guidance of Ancel Keys, a professor of the university during that time. Under this experiment, 36 healthy young men volunteered to undergo a semistarvation experiment. The goal was to learn more about human starvation and refeeding after a period of starvation ends. One of the most notable aspects of this study was the profound impact on the participants' attitude and behavior patterns. Through the semistarvation period, participants reported they felt very irritable, moody, unmotivated, tired and introverted. They also reported a general preoccupation and obsession with food, with many becoming consumed with collecting recipes and cookbooks. Many participants also had jealous and hateful feelings towards others outside of the experiment that had more access to food (5).

While this study represents a more extreme example, it illustrates what can happen to one's psychological health when food is restricted to a large degree. There are similar patterns seen among chronic dieters. Those who diet often tend to become more obsessed with food, to the point where it can interfere with other areas of daily life.

Diets often take the joy out of eating

As you may know, I am a huge proponent of finding the joy in eating. This is because food is more than fuel or a means to survive. Aside from nourishment, food is a source of enjoyment, experience, culture, connection and so much more. Popular fad diets often promote a "one-size-fits-all" approach without the consideration of an individual's background, lifestyle or individual needs. They also tend to promote strict food rules. This can lead to people feeling anxious around food and shameful of their food choices if they don't stick to the "rules" they feel they need to follow. Realistically, everyone should eat to nourish themselves in a way that meets their individual needs and preferences, while honoring their connection to food. It's important to eat in a way that brings you peace with food, so you can maintain a lifelong healthy relationship with food and your body.

Shifting your focus to long-term solutions and forming a healthy relationship with food

Unfortunately, many go on a diet to meet our strict societal standards, such as attempting to meet the often unrealistic thin ideal we have created. Health looks different on everyone. As a society, we need to embrace the natural variation in body shape and size among us. Instead of focusing solely on weight, it's important to focus on building healthy habits that you can maintain for life. This way, it will be easier to achieve and maintain a healthy weight for you. Aside from that, there are many other markers of health outside of weight, such as blood work/labs, healthy digestion, feeling free and confident in your food choices, being able to listen to you body and honor what it needs, finding ways to incorporate regular, joyful exercise into your routine and much more.

If you need help ditching the diet mentality and shifting your focus to long-term health and well-being, a registered dietitian can help you build healthy habits that you can feel good about and that meet your unique needs. I offer one complimentary, 30-minute discovery call to anyone who would like to explore working together. Contact me to learn more!

Until next time,


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