I am not sure about overseas, but in India a phenomenon among gym-goers is very visible and most of us may have noticed it.
People often start looking softer, heavier, and visibly fatter very quickly after they stop training. Many of these individuals had previously lost fat after joining the gym, and therefore the research I discuss below directly speaks to this crowd.
Most people look at a former gym-goer who expands in four to six weeks and reach for the same explanation:
“He stopped training, so he burns less and is still eating the same. Surplus calories.”
That story is incomplete.
Over the last one and a half decades, I have spent overall spent hundred of hours in gyms, trained hundreds of athletes outside of gym, and observed hundreds in the gyms. The pattern is remarkably consistent. Many people gain weight surprisingly quickly after training stops, even when their overall lifestyle remains largely unchanged.
The explanation is usually reduced to the calories burned during exercise. But exercise itself contributes only a fraction of total daily energy expenditure. Most people who stop training do not simultaneously stop working, walking, climbing stairs, or carrying out daily activities. They remain active human beings.
The more important question is not:
“How many calories did the workout burn?”
It is:
“What metabolic processes disappear when training stops?”
A recent study provides an important clue.
The Research That Changes the Picture: https://www.nature.com/articles/s41366-026-02179-z
In a 2026 paper published in the International Journal of Obesity, researchers examined recreational athletes who lost weight while performing resistance training and consuming adequate protein.
Resting energy expenditure (REE) still fell by roughly 140 kcal per day, even in individuals who gained fat-free mass. In other words, the body can lower its baseline energy expenditure independently of how much muscle it currently carries.
That finding matters far beyond weight loss studies. It suggests that metabolism is not determined solely by muscle mass. The body can become more energy efficient even when lean tissue is preserved. This helps explain why the post-training weight rebound often appears larger and faster than many calorie-based models would predict.
The classic calorie argument treats expenditure as relatively fixed and focuses almost entirely on intake. But when training stops, several overlapping physiological shifts occur simultaneously. Together they create conditions that favour fat gain even when food intake appears broadly similar.
Component 1: Adaptive Downregulation of REE
The body does not keep resting energy expenditure permanently tied to current muscle mass. The study demonstrated this clearly: greater-than-predicted reductions in REE occurred despite preservation or increases in fat-free mass. Once the metabolic set-point shifts downward, every calorie becomes metabolically cheaper.
The system is now operating in a more energy conserving state. This is important because many people assume that as long as muscle mass remains reasonably intact, metabolism should remain unchanged.
The evidence suggests otherwise.
Component 2: Loss of the High-Cost Anabolic Sink
This may be the most overlooked mechanism. Resistance training is not merely an activity that burns calories for an hour in the gym. Training creates a continuous physiological demand for tissue repair, muscle protein synthesis, protein turnover, glycogen replenishment, cellular adaptation, and remodeling.
These processes require energy.
When training is occurring regularly, nutrients and energy are continuously being directed toward maintenance and adaptation. When training stops, much of this demand disappears. The workout itself may have lasted only sixty minutes. The adaptations it created operated around the clock.
When those adaptations are no longer required, the body loses a significant metabolic destination for incoming nutrients. From an energy-partitioning perspective, this effectively creates a surplus.
Component 3: Nutrient Partitioning Changes
During periods of regular training, incoming nutrients are preferentially directed toward recovery, repair, adaptation, and glycogen restoration. Training effectively creates a demand.
Remove the training stimulus and that demand weakens. The same nutrients that previously had productive destinations now face fewer competing pathways. As a result, a greater proportion becomes available for storage. This is one reason why focusing exclusively on calories burned during exercise misses much of the story.
The issue is not merely expenditure. It is where nutrients are being directed.
Component 4: The Indian Dietary Shift
This mechanism is particularly relevant in India.
In many Western populations, people who stop training often continue eating large amounts of animal protein because that remains part of their normal diet.
India is different.
A large number of gym-goers temporarily adopt a high-protein eating pattern while training – egg whites, chicken breast, whey protein, paneer, and other gym-associated foods. Once training stops, many abandon this pattern almost immediately.
- Ten egg whites become four chapatis.
- Chicken becomes extra servings of rice.
- Protein shakes disappear.
- Snacks, sweets, and traditional comfort foods return.
Two consequences follow:
- The thermic effect of food declines because protein is energetically expensive to process. Its very small in my view because, in India, we don’t eat stake or any meat that requires too much chewing. However, TEF difference is real.
- The nutrients that previously supported muscle remodeling and recovery are no longer required for that purpose.
The result is not simply a dietary change. It is a shift toward a lower-cost metabolic state occurring at exactly the same time that training-related demands have disappeared.
Why Exercise Calories Alone Don’t Explain It
The popular explanation assumes that the entire effect comes from the calories burned during workouts. But that does not fully fit what we observe. Exercise contributes only a portion of total daily expenditure. Most former gym goers continue to live active lives.
They work. They walk. They move. They are not suddenly confined to a couch.
Yet many still gain weight rapidly. The more plausible explanation is that stopping training changes the body’s entire energy economy.
- A lower REE.
- Reduced anabolic demand.
- Altered nutrient partitioning.
- Lower dietary thermogenesis.
All of these occur together.
Looking only at exercise calories ignores the much larger physiological system surrounding training.
Putting It All Together
You now have:
- A lower baseline metabolic burn through adaptive reductions in REE.
- The disappearance of a continuous energy-consuming anabolic process.
- Reduced demand for repair, recovery, and tissue remodeling.
- Altered nutrient partitioning that favours storage.
- A dietary shift that lowers the energetic cost of processing food.
The result is a positive energy balance driven largely by falling expenditure, changing metabolic demands, and altered nutrient allocation.
The calorie model is not wrong. Energy balance still governs body weight.
But the phrase “he’s eating more than he’s burning” tells us almost nothing about the mechanisms that created that imbalance. The more important question is why expenditure fell and why nutrients are no longer being directed toward the same destinations.
That is where the physiology lies.
And that physiology explains why so many former gym-goers in India gain weight rapidly after training stops even when they believe very little has changed.
Umesh Chhikara 