4 Common Myths About Metabolism

By Kelsey Chadwick, MS RDN

February 7th, 2025

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If you’re a listener of the Nutrition For Mortals podcast, you’ve probably heard Matt and Jen’s episode, Can You Hack Your Metabolism? If not, what are you waiting for? You can find the episode here. Today, we’ll debunk four common myths about metabolism that are often perpetuated by diet and wellness culture. These myths can make us feel like our metabolism is inefficient or needs "hacking," but the truth is much simpler and science-based.

What is Metabolism?

Metabolism refers to the chemical reactions in the body’s cells that convert food into energy. Essentially, it encompasses all the biochemical processes that sustain life. A significant portion of our energy expenditure goes toward essential functions like organ operation, hormone production, and digestion. Now, let’s address the myths!

Myth 1: Certain Foods and Supplements Can "Hack" Your Metabolism

Reality: Our metabolism is tightly regulated, and food doesn’t significantly alter its rate. Despite marketing claims, there’s no evidence-based research supporting the idea that supplements or specific foods can boost metabolism. “Metabolism-boosting foods” like caffeine or spicy foods have no measurable impact on metabolic rates in any sustained way. Similarly, supplements advertised with phrases like “magic cure” or “hack your metabolism” are purely marketing strategies aimed at increasing sales, not your metabolism.

Myth 2: We Have No Influence Over Our Metabolism

Reality: While it’s true that genetics, age, and sex play significant roles in determining our metabolic rate, we aren’t entirely powerless. Factors like getting adequate sleep, eating enough throughout the day, and incorporating regular movement into our routine can support our metabolism, helping it function efficiently. While there are factors outside of our influence, we can create habits that allow our metabolism to work as it should.

Myth 3: Digestion Rate Equals Metabolic Rate

Reality: Digestion and metabolism are two separate processes. The rate of digestion refers to the time it takes for food to travel through the digestive tract. This process is influenced by factors such as meal composition, intestinal length, and more. In contrast, metabolism refers to how our body’s cells convert food into usable energy, measured in calories or energy units. Importantly, metabolism occurs in our cells, not the digestive tract.

Myth 4: Losing Weight Increases Metabolism

Reality: Diet culture often promotes weight loss as a way to “fix” metabolism, but research shows the opposite. A study discussed in the Can You Hack Your Metabolism? episode, titled “Persistent Metabolic Adaptation 6 Years After The Biggest Loser Competition,” found that metabolism slows significantly after weight loss and caloric restriction. This slowdown is the body’s way of conserving energy.

In addition, restrictive dieting like the type seen on The Biggest Loser has emotional consequences, including low self-esteem, increases in depressive thoughts, and higher stress levels. Shows like this perpetuate the belief that intense and rapid weight loss through restriction and excessive exercise are the path to health and happiness. In reality, these types of behaviors can lead to profound physical and mental health challenges that we’ve discussed before in past blog posts.

Moving away from dieting and restrictive eating is challenging, but it’s possible. If you need support, our team offers personal nutrition counseling to help you nourish your body and build a sustainable relationship with food. If you’re ready to step away from diet culture and embrace evidence-based nutrition, reach out to us today. We’d love to support you on your journey!

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Reference:

Fothergill E, Guo J, Howard L, Kerns JC, Knuth ND, Brychta R, Chen KY, Skarulis MC, Walter M, Walter PJ, Hall KD. Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity (Silver Spring). 2016 Aug;24(8):1612-9. doi: 10.1002/oby.21538. Epub 2016 May 2. PMID: 27136388; PMCID: PMC4989512.