[quote loveisagirlnameddaisy]@MatildaIThink this is something that we've researched extensively and there's different schools of thought on calories in=calories out. I'm about to buy Why We Eat and i think that looks at diet and metabolism as being far more complex than just calorie deficits.
He used MFP most of last year when he lost weight, weighed and logged everything, was on about 1800 cals per day (he's 6'4") and some weeks lost nothing. Would love explanations for why.[/quote]
Without specific investigation I could not give you an exact reason, but in every case where there have been controlled trials into people who say they cannot lose weight regardless of what they eat, when in residential monitoring they either lose weight if sticking to the controlled diet, or eat more than they report eating of monitored.
There can be variations in base metabolic rate and with only calorie reduction and no exercise it will decline slightly, but even then you are only talking about a maximum of 5% variance.
The biggest factor is almost always poor estimates/measure of portion size, outside of specifically weighing every ingredient weight/volume is under-reported by 20-50%. Often the milk in tea and coffee is ignored or under-reported, especially as some people will drink more hot drinks to make up for lower food intake, many people ignore the fats used in cooking, those can add up. Finally there is alcohol, which many people either ignore or underestimate.
People also tend to overestimate the amount of calories they burn, activity trackers can bring that error rate down, but their accuracy rates are still +/- 10% and calculating calories from exercise is subject to other variables (total weight, muscle mass).
Nutrition and huger do play a large part, low carb diets tend to work well for many people not because of any magical trick, but because when removing carbs from the diet blood sugar tends to stabilise and vary little at any point, that removes one of the triggers of hunger (blood sugar levels falling lower than previously normal), there is in theory a tiny benefit to weight loss from ketosis, but it is not big enough to generate and substantial weight loss. Things like green vegetables to bulk out meals, as well as protein which takes longer to digest so leaves one feeling full for longer are also important, as is making sure one is properly hydrated, especially during weight loss.
From experience of friends and family I have always seen that men find it easier to lose weight through exercise rather than deep cuts to calorie intake. The biggest example is my brother, who is in his late thirties (and had not exercised since he was 14), last year, early in the lockdown he was just over 18 stone, he decided he did not want to be fat any more, so started exercising and with little else to do during lockdown the weight fell off him. By the end of last September he was 12st 0lbs and had a six pack, more than a year later he is still only 12st 6lbs and whilst not got the defined six pack he has a totally flat stomach. He was at one point eating 3,000 calories a day and still losing weight as he was exercising for 6-8 hours a day.
The issues with weight loss are rarely physical, they are almost always phycological and our own minds are our greatest assets, but they can also be somewhat of a liability.