I frequently hear this complaint from people, but I don't buy it. Even ChatGPT is on my side. Check out this AI-fueled discussion on the issue.
Me to ChatGPT: I would like to discuss with you the body weight gain issue.
A lot of people Google stuff like “gaining weight without eating,” but honestly, I’m not buying it.
Sure, in rare cases—like if someone has a serious medical condition, say kidney issues—they might gain weight from water retention. But that’s not typical, and without treatment, it can be dangerous or even life-threatening.
Some meds can cause water retention too, which can show up as weight gain. But again, that’s a specific situation.
Here’s the bottom line: if your body’s not getting energy from food, it has to pull from what it already has—fat stores, glycogen, even muscle. You will lose weight. That’s just how it works.
People sometimes talk about the body going into “survival mode” and slowing down the metabolism to hang onto energy. And yeah, metabolism does slow down to conserve fuel—but if there’s no food coming in, there’s still nothing to store. Slower or not, the body keeps burning what it’s got.
So when I hear someone say they’re gaining weight without eating anything, I have a hard time believing it. What's your take on this?
ChatGPT: Your understanding is generally accurate. Weight gain ultimately comes down to an excess of calories consumed over calories expended. If someone is genuinely not eating and is gaining weight, it would defy the laws of thermodynamics.
There might be several reasons why people think they're gaining weight despite not eating much:
Water Retention: As you mentioned, certain health issues or medications can cause water retention, leading to a temporary increase in weight.
Misinterpretation of Eating Habits: Sometimes people might think they are eating very little, but they underestimate their calorie intake. They might be consuming more calories than they realize.
Metabolism Misunderstanding: There's a common myth about metabolism slowing down to a point where one gains weight even with very little food. While metabolism can adjust to lower calorie intake, it doesn't defy the basic principle that weight gain requires a surplus of calories.
Medical Conditions: Certain medical conditions can affect weight, and it's essential to consider these possibilities. For instance, issues with the thyroid gland can influence metabolism.
Muscle Mass Gain: If someone is engaging in strength training or resistance exercises, they might be gaining muscle mass. While muscle is denser than fat, it doesn't accumulate in large amounts quickly, and the overall effect on weight should align with the principle of calorie balance.
It's crucial for individuals facing unexpected weight changes to consult with a healthcare professional to rule out underlying medical conditions and get personalized advice. The basic principle remains: without a surplus of calories, sustained weight gain is not possible.
Me: After a workout or any kind of physical activity, your muscles can get a little inflamed from microtears, and that can cause some short-term water retention. So yeah, you might see a tiny bump in your weight right after. But even then, if you’re not eating and not taking in any energy, your body’s still going to lose weight—no matter what’s happening with muscle recovery. Right?
ChatGPT: Absolutely, you're correct. After intense physical activity, particularly resistance training or high-intensity workouts, muscles may retain water temporarily due to inflammation and the repair processes. This is often referred to as "water weight."
However, if someone is not eating and, as a result, not taking in enough energy to support the body's basic functions and the recovery process, the overall impact will be weight loss, not gain.
The temporary water weight associated with muscle inflammation is not a gain in body fat. It's a short-term phenomenon linked to the body's repair mechanisms. As the body heals and inflammation subsides, any temporary water weight will be lost, and the overall trend, given a caloric deficit, will be a reduction in body weight.
In summary, consistent weight gain without an increase in calorie intake is not feasible. The body, in the absence of external energy (food intake), will turn to internal stores, leading to weight loss over time.
Me: That just backs up what I’ve been saying. Unless we’re talking about serious health problems or certain medications, stuff like working out, thyroid issues, or whatever else can’t make you gain weight if you’re not eating. No food means no extra energy to store—so weight gain just isn’t happening.
What’s way more likely is that people are misreading what’s going on, don’t really understand it, or—let’s be real—are lying to themselves (or others).
ChatGPT: Yes, you are correct in your understanding. In the absence of external energy intake (food), the body will not gain weight. Weight gain is fundamentally linked to a surplus of calories — consuming more energy than the body expends. If a person is not eating, there's no external source of calories to lead to weight gain.
While there are conditions or circumstances that can cause temporary fluctuations in weight, such as water retention or inflammation after exercise, these are distinct from gaining body fat. Moreover, any water weight gained in these situations is generally short-lived.
Sometimes, as you mentioned, there might be misinterpretations, misunderstandings, or even misinformation. It's crucial to rely on accurate information and a solid understanding of the body's mechanisms when discussing topics related to weight management.
So stop fooling yourself. Be honest, take this seriously, and you can lose the weight.
That’s why I put together a super simple weight-loss plan you can actually stick to. It helps you drop pounds naturally, right from home—no gym required.