"rigorous diet" is a correct and usable phrase in written English
You could use it to talk about a diet that is very strict and requires a lot of self-discipline. For example, "I'm starting a rigorous diet to lose weight before summer."
Adjusting psychologically to life after weight-loss surgery is crucial, as is adopting a rigorous diet and exercise routine.
The father of a newborn infant must observe a rigorous diet for a week or so after the infant's birth.
Mr. Goyal said he was on a rigorous diet and exercise schedule for the last two months to make sure he was fit for the mountain hiking involved.
As well as committing him to a rigorous diet and exercise regime, Harris admitted the part "brings up a lot of homophobic insecurities within myself".
His asthmatic attacks were frequent and disabling and not much helped either by a rigorous diet or by the fumigations which in time were to blacken the bedstead and cork-lined walls of his room in the Boulevard Haussmann.
She sought a doctor's advice about losing weight and was put on a rigorous diet: at the start of 1958, she weighed something between 13 and 15 stone; by that summer, she was around 10 stone.
It's not surprising that it disappears when people go on rigorous diets.
Inspired by Manning's journey (or gimmick, depending on how you look at it), the show follows 10 trainers as they abandon their rigorous diets and exercise routines to intentionally gain as much weight as possible, under medical supervision, for four months.
Our findings might open perspectives for much more feasible therapeutic strategies than the rigorous dieting regimens that few people are able to follow.
PKU can result in several problems in untreated patients, including intellectual disability, liver failure, and reduction of life expectancy [ 1, 2], and its nutritional therapy is accomplished by rigorous diets based on Phe-free protein substitutes, either mixtures of free amino acids or protein hydrolysates [ 3].
As a spectator of an MMA fight, you're always well aware of the gym hours, the rigorous conditioning schedule, the strict diet, not to mention the time it takes to become proficient in every phase of fighting.
