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Barriers to weight loss

Willpower or biology: Who is in the driver’s seat?

We often aim to eat less and move more in order to lose weight. But many aspects of our eating choices and physical activity are determined by complex biological systems that lie beyond our willpower.

4 min. read
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Every day we make hundreds of decisions, big and small. Many of these decisions are good, but sometimes we later realise that we’ve made a poor decision.  Sometimes, we even know we are making a poor decision as we make it.

This is often the case when it comes to our relationship with our food. We blame ourselves for not making the right decisions to meet our weight goals and therefore don't always succeed in managing our weight. We try to eat less and move more, but we don’t always succeed in managing our weight.

But what if we have far less free will than we think we do?

Thinking fast and slow

We can thank the behavioural economist Daniel Kahneman for helping us to understand that we have less conscious control over the decisions we make, than we think we do. In fact, we make many decisions without being aware of it.

He calls this System 1 thinking. It’s fast, intuitive and unconscious, like picking a t-shirt out of the closet, or tying your shoelaces.

System 2 works differently. Let’s say you have an important date. You might spend a lot of time trying on different clothes and asking your friends for advice. This is System 2 thinking – slow and deliberative.

System 1 and System 2 in weight regulation

How do System 1 and System 2 work when it comes to weight and appetite regulation?

Many people have thought long and hard about their weight goals and the food that they want to eat. This might mean that they diet or make sure they don’t have second servings. This is what most people would think of as willpower. Willpower works under the jurisdiction of the System 2.

But sticking to food and weight goals is made more difficult because of the plans System 1 has in place. Those plans are governed by the rules of survival game that is no longer relevant. The rules of survival favour over consumption of high-energy foods and vigorously protect us from weight loss.

"A combination of therapies and approaches that address multiple mechanisms involved in weight regulation is likely to be most efficient way to manage obesity."

-Berthoud HR et al. Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms.

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Work your biology

Science has proven that if we want to lose weight and keep it off, willpower is far from being the only factor. In fact, it plays a much smaller role when it comes to weight regulation than we used to think.

Weight is controlled by many processes and some of them are outside of our conscious awareness. That is why a combination of therapies and approaches that address multiple mechanisms is likely to be the most efficient way to manage obesity, according to the research group from Louisiana State University.

Fortunately, you do not need to do it alone. Scheduling an appointment with a trained healthcare provider to make a personalised treatment plan is an important first step to start tackling the challenge and make your biology work for you.

  • Berthoud HR, Münzberg H, & Morrison CD. Blaming the Brain for Obesity: Integration of Hedonic and Homeostatic Mechanisms. Gastroenterology 2017; 152:1728–1738.
  • Hall K & Hammond RH. Dynamic Interplay Among Homeostatic, Hedonic, and Cognitive Feedback Circuits Regulating Body Weight. American Journal of Public Health 2014; 104:7.
  • Nair P. QnAs with Daniel Kahneman. PNAS 2013; 110(34),13696.


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Talk to your weight management provider about treatment options that could prevent the weight you lose from coming back.

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