Factors that can affect true fat loss
Eating less and moving more is a good start, but alone is not enough. People get frustrated when the numbers don't seem to add up or their results don't match their expectations. It would be simple if all we had to do was count the calories we eat and what we think we expend during the day, but unfortunately fat loss is much more complicated than that. Here is a list of just some of the factors to consider with fat loss, and is by no means a comprehensive list.
1) Food labels can be off by as much as 25%
2) The amount of energy a food contains in the form of calories is no necessarily the amount of energy we absorb, store, and/or use. (The food we eat has to be digested and processed by our unique bodies and also depends on the kind of food we eat)
3) Resistant starches: a type of starch that isn't fully broken down and absorbed but rather turned into short chain fatty acids by intestinal bacteria. (this can lead to some unique health benefits).
4) Energy out part of the equation has many parts to it: Resting Metabolic Rate (RMR), Thermic effect of eating, Physical activity done, Non-exercise activity thermogenesis (NEAT). Each of these factors are highly variable. (keep in mind that your body tries to keep your weight steady when you take in less energy and start to lose weight)
5) Adaptive Thermogenesis:It is a critical component of energy balance in the body and is normally a protection against obesity. It can also cause the body to decrease is metabolic rate by 50% to defend against times of starvation, and it increases the hunger signals in the body to cause us to crave more (this is why you need to lose weight slowly)
6) Insulin resistance: associated with inflammation, obesity, and gut health.
7) Gut microbiome: the bacteria that make up our bodies play a significant role in bodily functions such as digesting food, appetite, regulating our metabolism, and immune system function.
8) Thyroid issues
9) Xenoestrogens: endocrine disruptors
10) Stress and sleep.
11) Personal factors: age, genetic makeup, gender, how much body fat you have, medicines, hormones, and more....
So just understand that this is all complex. Food intake and body composition are governed by a mix of physiological, social, economic, and lifestyle influences. The best advice is to create an environment that encourages good food choices and discourages poor ones. You also want weight loss to be relatively slow, in order to maintain muscle mass and minimize adaptive metabolic responses.