We are told again and again that obesity exists because we do not exercise enough. Move more, burn more calories, and the problem will disappear. It sounds logical—but it does not match what we see in real life.
People exercise more than ever. Gyms, fitness apps, smart watches, workout videos, and step counters are everywhere. Many people work out faithfully several times a week. And yet obesity keeps rising. For example, obesity peaked among middle-aged adults (40–59), with a 46.4% prevalence in 2021–2023, higher than older (60+) groups. If lack of exercise were the main cause, weight should be falling—not climbing, among middle-aged adults who are expected to be more active compared to those older in age.
Exercise is good for you. It improves heart health, conditions your lungs, strengthens muscles and bones, lifts mood, sharpens thinking, and improves overall fitness. But exercise does not control hunger. And hunger is what controls how much we eat.
Hunger is not a choice. It is a command from the brain. Your brain decides when you need food based on signals about energy, nutrients, and fuel availability. If those signals say something is missing, the brain increases hunger—no matter how old you are or how much you exercise.
If your diet lacks nutrients, your brain will push you to eat—no matter how many miles you run or how many calories you burn. You can burn 400 calories in the gym and eat them back in minutes if your brain is screaming for fuel.
The brain does not count calories. It tracks survival signals:
- Is energy stable?
- Are nutrients sufficient?
- Is fuel available?
Why does the body track what you eat?
Because, every day, your body needs nutrients to replace about 330 billion cells, which is about 1% of your total cellular count. According to the Oak Ridge Atomic Research Center, approximately 98% of atoms in your body are replaced every year. You can accomplish this only by taking in a variety of foods, water and air on a timely fashion.
Now you can understand why the brain increases hunger when food quality is poor. Exercise cannot override that signal. You cannot outrun a brain that thinks it is starving.
This is why people often feel hungrier after workouts.
If the body is already struggling to get proper nourishment, exercise increases nutrient demand, to replace what was lost during energy production, breathing and sweating. If you respond with processed carbohydrates that provide quick relief that can turn a workout into a trigger for overeating instead of a tool for health. This is why so many people exercise faithfully and still struggle with weight. They are not lazy. They are not failing. They are working hard—but the system they are working in is broken.
This does not mean exercise is bad. It means exercise cannot fix a broken food system.
Weight loss starts in the kitchen, not the gym.
Food quality determines whether your body can regulate hunger and energy. When meals are nutrient-dense, hunger becomes more manageable rather than constant. Blood sugar stabilizes instead of spiking and crashing. Insulin levels fall between meals. Fat becomes available as fuel.
In that state, exercise helps the body use fuel more efficiently. Muscles become better at using both glucose and fat. Energy feels steady instead of draining. Recovery improves. Exercise supports metabolism instead of fighting it.
The real issue is not movement—it is nutrients. Modern diets are heavy in refined carbohydrates and poor in nutrients. These foods spike blood sugar quickly and leave the body nutritionally unsatisfied. Insulin rises pushing glucose into cells, blood sugar starts to drop, and the nerve cells sense low available energy. Hunger increases. Exercise cannot fix that.
Fix the food first. Then let exercise support the system instead of fighting it.
When meals are built around real foods—proteins, healthy fats, vegetables, fruits, nuts, and whole foods—the body begins to trust its nutrient supply chain. Hunger calms down. Energy stabilizes. Fat becomes accessible. In that state, exercise becomes a powerful ally instead of a constant struggle.
Exercise is an accessory. Food is the foundation.
Next in the series:
Chili Peppers, Heart Attack, and Stroke
John Poothullil practiced medicine as a pediatrician and allergist for more than 30 years, with 27 of those years in the state of Texas. He received his medical degree from the University of Kerala, India in 1968, after which he did two years of medical residency in Washington, DC and Phoenix, AZ and two years of fellowship, one in Milwaukee, Wisconsin and the other in Ontario, Canada. He began his practice in 1974 and retired in 2008. He holds certifications from the American Board of Pediatrics, The American Board of Allergy & Immunology, and the Canadian Board of Pediatrics.During his medical practice, John became interested in understanding the causes of and interconnections between hunger, satiation, and weight gain. His interest turned into a passion and a multi-decade personal study and research project that led him to read many medical journal articles, medical textbooks, and other scholarly works in biology, biochemistry, physiology, endocrinology, and cellular metabolic functions. This eventually guided Dr. Poothullil to investigate the theory of insulin resistance as it relates to diabetes. Recognizing that this theory was illogical, he spent a few years rethinking the biology behind high blood sugar and finally developed the fatty acid burn switch as the real cause of diabetes.Dr. Poothullil has written articles on hunger and satiation, weight loss, diabetes, and the senses of taste and smell. His articles have been published in medical journals such as Physiology and Behavior, Neuroscience and Biobehavioral Reviews, Journal of Women’s Health, Journal of Applied Research, Nutrition, and Nutritional Neuroscience. His work has been quoted in Woman’s Day, Fitness, Red Book and Woman’s World.Dr. Poothullil resides in Portland, OR and is available for phone and live interviews.To learn more buy the books at: amazon.com/author/drjohnpoothullil
Visit drjohnonhealth.com to learn more. You can also contact him at john@drhohnonhealth.com.
Or follow us on:
Instagram: instagram.com/DrJohnOnHealth
Facebook: facebook.com/JohnOnHealth
Youtube : @DrJohnPoothullil
For more great health and lifestyle content, see here.
Explore more insights at https://dailymailusa.com/.
