Your body is good at storing fat—oh, thanks, evolution! Here’s how to game your system

Your body is good at storing fat—oh, thanks, evolution! Here’s how to game your system

Your body is good at storing fat—oh, thanks, evolution! Here’s how to game your system

Early humans got really good at holding onto fat reserves to survive. But that isn’t helping us manage weight in the 21st century.

Jennifer Clark, PhD
Last updated:
February 28, 2023
5 min read
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We owe a lot to evolution, but honestly, your genes could care less about your jeans size or how you feel about your abs. Here’s why: For at least 200,000 years the modern human body has been programmed to care about survival above all else—–specifically, living to an age where you can have kids and pass on your genes. (And—survival of the fittest!—your kiddos and their kiddos must pass them on, too.) And because of that, it’s developed the ability to store fat to help support pregnancies, a large brain, and the energy to hunt and gather.

Although you may not like how it looks, fat serves many critical functions in your body. When you eat food, the energy you don’t burn off in the short term is stored as fat. Tons of other animals do it, too, BTW—and it allows our bodies to have a reserve for times when we don’t have enough to eat or during times of illness. (Think of it like a silo storing grain or silage to feed the animals during the winter.) Fat also insulates your body so you don’t get too cold, plus helps protect your muscles, bones, and organs. So you need a certain amount of fat to survive.

But that balance can tip toward an unhealthy amount of body fat—and too much of it can lead to serious health consequences like osteoarthritis, diabetes, and cardiovascular disease. These conditions probably weren’t really a thing among earlyHomo sapiens. Researchers have several theories about why obesity developed in humans—and how much of our weight may actually be ingrained in our DNA and not, say, due to a lack of willpower.

One of those theories suggests that there is no single set weight point. Instead, it proposes that your body has a set weight range that may respond to environmental factors; at the lower threshold, it promotes fat storage if it senses starvation, and at the upper threshold, it keeps you from stashing away excessive fat stores, which back in the day could help you avoid predators. Outside of this range, your body has mechanisms that kick in to help your body survive—which is why you may have experienced a weight plateau at some point. The idea is that the lower threshold hasn’t moved (or not by much) throughout evolutionary time but the upper limit probably has. This theory is called the “dual-intervention point model.”

So, in that theory, if the upper point of the set weight range moved, how was it possible? The “drifty gene hypothesis” may explain. Genetic drift, the foundation for this hypothesis, is a change in the frequency of occurrence of certain gene variants due to random chance. This can happen when populations separate from one another–say when early humans were on the move. When it comes to explaining the change in set weight range, as humans began to increase their safety from predators, the upper limit of fat storage was able to “drift” in some groups, where others maintained a “lower” upper limit, leading to a wider range of body mass over time. (And this is why some people struggle with obesity and others don’t.) 

Can you beat your genes?

OK, so is there anything you can do given the DNA you inherited from your ancestors? Well, you can start by adopting some of these age-old hunter-gatherer (and more modern) habits.  Such as:

  1.  Eat a diverse diet rich in plants–especially vegetables and beans that deliver lots of fiber and are high in micronutrients. Do you need to cut out meat? No. But focus on things that grow in the ground versus cluck or moo in the barnyard.
  2.  Limit ultra-processed foods that are generally higher-calorie and low in nutrients.
  3.  Include more movement in your day. 
  4.  In addition to regular exercise, try to just move more in general in your daily life. It’s called NEAT (non-exercise activity thermogenesis). While it’s not totally clear how it can play a role in weight loss, there’s evidence that things like walking your dog, folding laundry, and anything else that gets you sitting less and moving more can be beneficial. 
  5.  Spend more time with friends and family. Strong and rewarding relationships can reduce stress and may help with weight loss.
  6.  Focus on mindful eating and portion control. Appreciate your food and the hard work you have done to plan and prepare your meal. 

Consider medication to help with your weight care journey to help you with the biological factors that you cannot control. Not exactly a hunter-gatherer habit, but a way Found can help.

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Published date:
February 28, 2023
Meet the author
Jennifer Clark, PhD
Scientific Consultant


  • Speakman JR, Levitsky DA, Allison DB, et al. Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity. Dis Model Mech. 2011; 4(6):733-745.
  • Speakman, J.R. (2016). Evolution of Obesity. In: Ahima, R.S. (eds) Metabolic Syndrome. Springer, Cham.
  • Pontzer H, Wood BM, Raichlen DA. Hunter-gatherers as models in public health. Obes Rev. 2018; 19(Suppl. 1):24–35.,Obesity%20and%20metabolic%20disease,hunter%2Dgatherers%20and%20subsistence%20farmers
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