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The Science of Calories: Why Weight Loss Isn't Just About Cutting Calories

Writer's picture: Fatima IqbalFatima Iqbal
Choosing healthy foods

In 2018, a study in the Journal of the American Medical Association (JAMA) challenged the widely held belief that reducing daily caloric intake by 500 calories would guarantee a steady one-pound weekly weight loss. However, the reality of weight management is far more intricate, with multiple factors influencing our bodies' energy balance.



The Caloric Reduction Fallacy:


Reducing caloric intake by 500 calories a day does not always equate to a steady one-pound weekly weight loss. The reality is that our bodies' calorie balance is influenced by numerous factors, including lifestyle and hormones. While caloric reduction plays a role in weight loss, it is only one piece of the puzzle.



The Role of Appetite Control:


Our appetite control circuitry is a complex system influenced by various hormones and neurotransmitters. When we reduce calorie intake, our bodies initiate adaptive mechanisms. For every kilogram of weight lost, our energy expenditure decreases by approximately 25 calories. Simultaneously, appetite increases, driven by hormones like ghrelin. This means that while calorie restriction helps with weight loss initially, it also raises hunger levels, making it challenging to sustain the restriction over the long term.



CALERIE2 Trial:


The CALERIE2 trial provides valuable insights into this phenomenon. Initially, participants in calorie restriction programs often succeed in cutting calories, experiencing weight loss. However, by the 12-month mark, many individuals relax their efforts. As weight decreases, appetite rises, creating a challenging battle. Had they persisted with calorie restriction, weight loss could have continued, but the reality of fighting increased appetite often hinders long-term success.



The Set Point Conundrum:


The notion of a "set point" weight, a level at which our bodies are comfortable and resistant to change, raises questions about the obesity epidemic. If our bodies truly regulated weight, why is obesity on the rise? The answer isn't simple. The shift towards diets rich in processed and high-calorie foods may be altering our set point, making it increasingly difficult to maintain a healthy weight. High-carb, low-fat diets may contribute to this shift by increasing insulin production, promoting fat storage, intensifying hunger, and reducing energy expenditure.



Low-Fat vs. Low-Carb Diets:


Studies comparing low-fat and low-carb diets have shown that differences in weight loss outcomes are minimal. However, the type of food consumed matters greatly. Ultra-processed foods, which are prevalent in modern diets, often contain unhealthy fats and high levels of added sugars. These foods can disrupt the body's natural regulation of energy balance.


Eating unhealthy foods

The Impact of Ultra-Processed Foods:


A study conducted at the National Institutes of Health (NIH) compared ultra-processed and unprocessed diets. The results were telling. Those on ultra-processed diets consumed, on average, 500 more calories per day and experienced weight gain. In contrast, low-fat diets that focused on whole, unprocessed foods showed the best results for weight loss and reduced overall energy intake.



Conclusion:

Weight management is a multifaceted challenge that extends beyond simple calorie counting. To succeed in achieving and maintaining a healthy weight, it's crucial to understand how our bodies respond to calorie reduction, the intricate role of appetite regulation, and the detrimental impact of ultra-processed foods on energy balance. While various diet approaches may yield results, focusing on a low-fat diet composed of whole, unprocessed foods appears to be a more effective and sustainable strategy for long-term weight management.

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