GPSGuided wrote:MrWalker wrote:CasualNerd is quite correct. Its biology not physics.
At the core of biology, it’s physics.
All that insulin resistance etc and etc are subset events under a basic caloric in-out framework. Clinically no individual under caloric negative balance can maintain the same weight. Those research knowledge are such good excuses for those who aren’t willing to put the hard work into weight loss, and great for the profit making diet industry.
I agree that if you don't eat at all then you will lose weight, but beyond that it's not so simple.
The number of calories you need each day is based on the average BMR (basal metabolic rate). This is the amount of energy you use up while resting (i.e the energy needed just to keep your heart beating, brain functioning, etc). The BMR accounts for about 70% of your daily calorie expenditure. But like any biological value BMR has wide variability. A standard rule of thumb is that most biological values (height, heart rate, hemoglobin value, etc) have a coefficient of variation of about 20%. That means that about 1/6th of people will be 20% higher than the average and 1/6th will be 20% lower than the average. Within our bushwalkers here, there would be some of us who have a BMR 50% higher than others.
The effect of this is that if you feed a group of people identical diets, some will lose weight, some will maintain weight, and some will gain weight. Then there are factors that can turn your normal BMR up and down. I think this is what CasualNerd was referring to. Carbohydrates, fat and protein have affects on your BMR and can increase or decrease it, so that some types of diets can make it harder or easier to lose weight, while maintaining the same calorie intake.
So the simple idea of calories in and calories expended ignores this huge individual variation.