Sustainable fat loss requires patience, persistence and proper planning. — 123rf
Few people realise how much humans are built to store fat efficiently.
This is a genetic disposition shaped over millions of years during our evolution.
But while our bodies are excellent at holding on to fat, they are also extraordinarily bad at giving up any acquired fat reserves.
This creates a major challenge in today’s world, where food is overly abundant.
The gap between our ancient biology and modern lifestyles explains why losing weight often feels like fighting against our own nature.
That is because weight loss is often really a fundamental battle against our own genes.
The column today looks at how human fat storage evolved, the biological systems that resist fat loss, and evidence-based strategies to manage this struggle.
Built for scarcity
To understand why fat is so hard to lose, we need to look back at our evolutionary past. Humans have been evolving for around three million years and for much of human history, food was scarce and unpredictable.
Those who could store extra calories as fat had a better chance of surviving famine, heavy exertion, or illness.
Also, fat was not just energy – it also insulated the body and protected organs, and allowed humans to survive in a variety of challenging environments.
Fat is especially efficient at storing energy: it provides nine calories per gram, compared to just four calories per gram from carbohydrates or proteins.
Importantly, the human body never evolved a way to sense “too much” fat because it has no concept of “excess” fat.
From an evolutionary perspective, more fat always meant a better chance of survival. As a result, when calorie intake exceeds expenditure, the body keeps storing fat with no natural limit.
In olden times, fat storage was considered ideal as those who stored fat could survive food scarcity. Photo: TOTAL SHAPE/Pexels
Our biology is built for scarcity, but we now live in an environment of chronic calorie excess.
No fat loss allowed
Whenever we use our brains to motivate ourselves to lose weight by eating less or exercising more, we often do not realise that our bodies see the idea of weight loss as a threat to survival.
Such a perceived threat activates powerful automatic defence mechanisms within the body to protect its fat stores and regain any lost weight as soon as possible.
One major concept to understand is the “metabolic set point”.
This set point is based on the theory that each body has a target weight range defined/influenced by genetics and long-term habits.
When body weight drops, hormones increase hunger and reduce energy expenditure to push the weight back up to the metabolic set point.
Long-term overeating can even raise this set point, making it harder or even impossible to achieve a lower healthier weight.
At this point, it should be noted that there is evidence that the metabolic set point may already start to be established from the age of two onwards, though it is probably still significantly influenced by diet and lifestyle until early adulthood, when it becomes a rigid weight baseline.
Hence, chubby young children may be cute, but they are also potentially heading towards a future of weight challenges.
The body defends fat stores through several mechanisms:
• Adaptive thermogenesis: After weight loss, the body’s metabolism slows more than expected.
The basal metabolic rate (BMR) can drop 15–20% below previous levels.
For example, losing 10 kgs may cause one to burn 200–300 fewer calories per day.
Our bodies see the idea of weight loss, whether through reduced consumption or increased exercise, as a threat to survival. Photo: GUSTAVO FRING/Pexels
This metabolic slowdown, driven by lower thyroid hormone levels and reduced nervous system activity, persists even after weight returns to the original metabolic set point. In fact, adaptive thermogenesis can provoke the body to gain even more weight beyond its original metabolic set point.
• Hormonal regulation, especially by the following hormones:
Leptin: Produced by fat cells, it signals fullness of the stomach and satiety. As fat mass drops, leptin levels fall sharply, increasing the sensation of hunger.
Ghrelin: Known as the “hunger hormone,” the level rises during dieting, making it harder to stick to calorie restriction.
Cortisol: Stress and calorie restriction raise cortisol, which promotes visceral fat storage and loss of muscle tissue, further lowering metabolism.
Insulin: While weight loss is known to improve insulin sensitivity, it also makes fat storage more efficient when calories return, as the body prioritises rebuilding fat stores. Basically, one can get fat again faster with insulin.
• Fat cell behaviour: Fat cells shrink during weight loss but they do not disappear. Once calorie intake rises again, these existing cells quickly refill, making weight regain easy.
Together, these processes make weight regain very common after any attempt at losing fat.
In fact, around 76% of dieters regain lost weight within five years, and another 10-20% can end up heavier than before attempting to diet.
Notably, long-term overeating prior to dieting can alter gene activity in fat cells – they develop an epigenetic memory of obesity – and this makes them better at storing fat and predisposing the body to regain weight significantly faster after any loss.
Sumo wrestler paradox
The physiology of sumo wrestlers offers an interesting story.
Despite having 30 to 40% body fat, active sumo wrestlers often stay metabolically healthy, with surprisingly low rates of diabetes and heart disease.
This is because most of their fat is subcutaneous (under the skin), not visceral (around organs).
Sumo wrestlers train intensely – up to six hours daily. This amount of effort preserves muscle mass and supports metabolic health.
They also show higher levels of “adiponectin” (a hormone that improves insulin sensitivity) and benefit from exercise-driven increases in growth hormones and testosterone.
Even their high-calorie diet includes nutrient-rich foods.
But once wrestlers retire and stop training, their health often declines rapidly.
Fat shifts quickly from subcutaneous to visceral stores, adiponectin levels drop, and risks of diabetes and heart disease rise.
This shows that metabolic health depends not just on body fat percentage, but also on lifestyle and fat distribution.
Strategies for sustainable weight control
Approximately 75% of Americans are overweight or obese, and 50-70% are actively trying to lose weight at any given time. Ironically, large studies show that repeated weight-loss attempts are often associated with long-term weight gain.
Nearly 76% of dieters regain lost weight in five years. Photo: SHVETS PRODUCTION/Pexels
Because the body strongly resists fat loss, success comes from working with biology, not against it.
The best results come from combining diet, exercise, stress management, and behavioural strategies.
Key approaches include:
• Maintain a modest caloric deficit: A small deficit (cutting 200-500 calories per day) is more sustainable than a swift, severe restriction, which will certainly provoke metabolic and hormonal reactions.
Aim to follow a modest, gradual diet that avoids triggering the body’s strong defensive fat-retention responses. Statistically, this works better in the short term where success rates are around 60–70% over 12 months, but long term success rates still fall to 20–30% within five years. The downside is that any weight loss will be limited and gradual.
• Prioritise protein and fibre: Protein (1.6-2.2g per kg body weight per day) preserves muscle and supports metabolism, while both protein and fibre increase satiety and help reduce overall calorie intake. Whole, nutrient-dense, organic foods are best.
• Exercise regularly:
Strength training: Two to three sessions weekly of weight training or resistance exercises increases/maintains muscle mass and improves the resting metabolic rate. Every kg of muscle burns about 13 calories per day at rest, which is more than the four calories per day per kg burned by fat.
Cardio and High Intensity Interval Training (HIIT): Alternating short bursts of intense, near-maximal effort exercises with brief periods of lower-intensity recovery or rest boosts calorie burn, fat oxidation, and insulin sensitivity, while helping to reduce visceral fat.
Manage stress and sleep: Poor sleep and chronic stress raise cortisol, a hormone which promotes fat storage. Aim to have seven to nine hours of good sleep daily as reducing stress helps regulate cortisol and other appetite hormones.
Stay hydrated: Water supports metabolism and drinking zero or low calorie liquids can prevent mistaking thirst for hunger. It may help to drink water whenever one feels hungry.
• Portion control and food quality: Mindful eating and limiting ultra-processed foods will help avoid hidden calorie surpluses (and other food contaminants).
• Maintain high energy flux: Combining a high level of physical activity with moderate food intake maintains a higher metabolic rate and can limit fat regain.
• Behavioural strategies:
Limit exposure to high-calorie foods by not keeping them accessible nearby
Be mindful of food portion sizes
Track weight and food intake to maintain awareness and motivation.
• Medical and surgical options: For severe obesity, there are more drastic options. Medications (such as GLP-1 receptor agonists) or bariatric surgeries (like stomach banding) can help reset the body’s physiology and bypass some of the biological resistance to weight loss.
These approaches tend to have higher success rates for significant long-term weight loss (up to 70-80%) although making lifestyle changes remains crucial for sustained results.
Summary
Our bodies evolved to store fat as a survival mechanism, and are never happy partners in any strategies to lose weight quickly.
The path to sustainable fat loss requires patience and proper planning.
A gradual, multi-faceted approach – modest calorie reduction, protein-rich diets, regular exercise, stress and sleep management, and long-term behavioural change – offers the best chance for lasting results.
This is because a gentle approach is less likely to trigger excessive responses by the body to maintain the metabolic set point.
The views expressed here are entirely the writer’s own.
