Fasting, meal timing & liquid calories

Fasting and time-restricted eating do cause weight loss — by cutting total intake (fewer hours means fewer snacks and less late-night grazing). But when calories are matched head-to-head against ordinary daily restriction, they are not superior (TREAT; a year-long alternate-day trial; a calorie-matched trial that added an eating window and saw no extra benefit). The value is behavioural simplicity, not metabolic magic. Evidence ●●●●○

Eating ‘6 small meals to stoke metabolism’ is false — the thermic effect scales with total calories, not meal count. Skipping breakfast does not wreck metabolism; in trials, people told to eat breakfast simply ate ~260 kcal/day more. One real caution: a fasting window with no protein target or resistance training can cost extra muscle — fixable by prioritising both.

The defining problem is poor compensation. Given 450 kcal/day as jelly beans, people cut back elsewhere and held weight; given the same as soda, they did not, and gained. Liquid calories are added on top of what you’d eat anyway. In a masked children’s trial, swapping a daily sugary drink for a sugar-free one meant ~1 kg less weight over 18 months. Evidence ●●●●○

100% juice and smoothies are liquid sugar with better nutrition and the same low-satiety problem — eat the fruit instead. On diet drinks, the randomised trials favour swapping sugar for water or a diet drink for weight loss; the scary headlines come from observational studies distorted by reverse causation. Hierarchy: water > diet drinks > sugar. Diet drinks are a fine bridge off sugar, not a health food.

Alcohol is 7 kcal/g (nearly as dense as fat) and, like sugary drinks, poorly compensated. Worse, the body prioritises burning it and pauses fat oxidation ~36% while it does. And it disinhibits eating — a drinking occasion adds ~256 kcal of food-plus-drink on average, with no later cutback.

Population data on moderate drinking and body weight are genuinely mixed and confounded — so this is not fear-mongering. But for anyone actively in a deficit, the mechanisms are unambiguous: extra un-counted calories, suppressed fat-burning, and weakened restraint all pull against you. It makes the math harder, not impossible. Evidence ●●●○○ for population weight; strong for the mechanisms