The meal may have been large without being filling
Volume and satiety are not the same thing. A plate that is mostly rice or roti with a small quantity of dal or vegetable can be substantial in energy and modest in the components most associated with reported fullness. Reviews of protein and satiety report that higher-protein meals increase reported fullness and reduce later intake relative to meals matched for energy but lower in protein.
This is the most actionable item on the page and the least dramatic. In a typical Indian meal structure it usually means the dal, curd, paneer, egg, fish or soya component arriving in a genuinely meaningful portion rather than as an accompaniment, without necessarily changing anything else about the plate.
Sources: [1]
Some of it is the clock, not the stomach
Ghrelin rises in anticipation of habitual meal times and falls after eating, which means part of what is felt as hunger is an expectation being cued rather than a shortage being reported. Somebody who has eaten a snack at five o'clock every day for years will experience something at five o'clock that is genuinely hunger and is not about the size of lunch.
The useful implication is that erratic timing generates confusing signals. A pattern of skipped breakfast, late lunch and a very late dinner produces anticipatory hunger at times that do not line up with when food actually arrives, and the mismatch is experienced as constant hunger rather than as a scheduling problem.
Sources: [2]
Sleep, and the week you cannot explain
In controlled conditions, restricting sleep lowered leptin, raised ghrelin and increased reported hunger and appetite in healthy volunteers, with the largest effect on appetite for calorie-dense foods. It is a small study and should not be over-extended, but it identifies sleep as a real variable rather than a moralistic aside.
Practically, this is why a week of unusual hunger following a week of poor sleep is not a mystery and not a failure. It is also why a hunger complaint that appeared alongside a schedule change is worth dating carefully before anything else is investigated.
Sources: [3]
The metabolic explanations worth measuring
Reduced insulin sensitivity with compensating insulin output is one candidate, and the compensation itself is well documented. The pattern people describe — heaviness an hour or two after a large starch-heavy meal, followed by hunger sooner than expected — is a common presenting story in that setting, though the experience by itself does not establish the mechanism.
Thyroid function is another, and reviews are candid that the symptom list associated with it is broad and non-specific, which cuts both ways: it is worth checking precisely because it cannot be ruled in or out from how somebody feels. Both of these are cheap to measure and impossible to settle by reasoning about a plate.
A symptom that fits a mechanism is not evidence of that mechanism in an individual. Each of these explanations is a reason to measure, and none is a conclusion.
A history of dieting changes the baseline
If there has been a period of substantial weight loss in the past, the appetite being experienced now may be operating from a shifted baseline: appetite-regulating hormones were found to remain altered a year afterwards, in a direction favouring greater intake.
That finding is worth stating plainly because of what usually gets said instead. Somebody who lost weight, regained it, and now describes constant hunger is routinely told they lack discipline. A persistent hormonal adaptation is a better-supported explanation than a character defect, and it is the reason this service does not sell a rapid method.
Sources: [5]
How to make the complaint investigable
Write down, for a week or two: when meals happened, roughly what was on the plate, when hunger arrived relative to them, and how the previous night's sleep was. Two weeks of that turns 'I am hungry all the time' into a pattern that can actually be examined, and it frequently answers the timing and composition questions without any test at all.
For what remains after that, the relevant markers are glucose handling, insulin, thyroid function, and a full blood count, since fatigue and hunger get confused with one another often enough to be worth separating. That is a panel and a clinical reading, not a search result.