diet

¹ American  

[dahy-it] / ˈdaɪ ɪt /

noun

1. food and drink considered in terms of its qualities, composition, and its effects on health.

   The ad shows milk and dairy as a wholesome part of our daily diet.

2. a particular selection of food, especially as designed or prescribed to improve a person's physical condition or to prevent or treat a disease.

   A diet low in sugar is often recommended for diabetes prevention.

3. a selection of food that emphasizes caloric restriction or otherwise limits the amount a person eats, usually intended to induce weight loss.

   No pie for me, I'm on a diet.

4. the foods eaten, as by a particular person or group.

   The Mediterranean diet consists historically of fish, fruit, vegetables, whole grains, and nuts.

5. food or feed habitually eaten or provided.

   The rabbits were fed a diet of carrots and lettuce.

6. anything that is habitually provided or partaken of.

   Television has given us a steady diet of reality shows and police procedurals.

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adjective

1. suitable for consumption as part of a selection of food intended to induce weight loss.

   I usually drink diet soft drinks.

2. formulated to be lower in calories, fat, sugar, etc. than a similar food.

   The diet version of the cookie does taste different.

verb (used without object)

diets, present (3rd person singular) dieted, past participle, past dieting present participle

1. to select or limit the food one eats to improve one's physical condition or to lose weight.

   I've dieted all month and lost only one pound.

2. to eat or feed according to the requirements of a particular or prescribed selection of food.

verb (used with object)

diets, present (3rd person singular) dieted, past participle, past dieting present participle

1. to regulate the food of, especially in order to improve the physical condition.

   They dieted the dog to a healthy weight of 20 pounds.

2. to feed.

diet ² American  

[dahy-it] / ˈdaɪ ɪt /

noun

1. the legislative body of certain countries, as Japan.

2. the general assembly of the estates of the former Holy Roman Empire.

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diet ¹ British  

/ ˈdaɪət /

noun

1. 1. a specific allowance or selection of food, esp prescribed to control weight or in disorders in which certain foods are contraindicated

      a salt-free diet

      a 900-calorie diet

   2. ( as modifier )

      a diet bread

2. the food and drink that a person or animal regularly consumes

   a diet of nuts and water

3. regular activities or occupations

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verb

1. (usually intr) to follow or cause to follow a dietary regimen

diet ² British  

/ ˈdaɪət /

noun

1. (sometimes capital) a legislative assembly in various countries, such as Japan

2. Also called: Reichstag.  (sometimes capital) the assembly of the estates of the Holy Roman Empire

3. Scots law

   1. the date fixed by a court for hearing a case

   2. a single session of a court

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Other Word Forms

Derived Forms

• dieter
  noun
• nondieter
  noun
• nondieting
  adjective

Inflected Forms

Participles

• dieting
  present
• dieted
  past

Conjugated Forms

Present

• diet
  simple
• diets
  simple
• have dieted
  perfect
• has dieted
  perfect
• am dieting
  progressive
• are dieting
  progressive
• is dieting
  progressive
• have been dieting
  perfect progressive
• has been dieting
  perfect progressive

Past

• dieted
  simple
• had dieted
  perfect
• was dieting
  progressive
• were dieting
  progressive
• had been dieting
  perfect progressive

Future

• will diet
  simple
• will have dieted
  perfect
• will be dieting
  progressive
• will have been dieting
  perfect progressive

Etymology

Origin of diet¹

First recorded in 1175–1225; Middle English noun diete “day’s journey, appointed day, way of living,” from Anglo-French, Old French diete, from Latin diaeta, from Greek díaita “way of living, diet,” equivalent to dia- dia- + -aita (akin to aîsa “share, lot”; the verb is derivative of the noun

Origin of diet²

First recorded in 1400–50; late Middle English, from Medieval Latin diēta “public assembly,” the same word as Latin diaeta with sense affected by Latin diēs “day”; see diet ¹

Explanation

Diet means the usual food and drink consumed by a person or animal. A healthy diet for your pet is not the same as your diet, so you shouldn't feed your dog all your table scraps. If you limit the number of calories you eat in order to lose weight, or restrict certain foods for your health, you can also call this a diet. If you want to lose 10 pounds by summer, you might have to go on a diet. In certain countries, the word diet, though pronounced the same, has a non-food related meaning: the diet is the legislative branch of the government in countries like Japan.

Example Sentences

See Examples For:

diet diets dieted dieting

At worst, eating a diet of 100 percent UPF compared to a diet with no UPF might cause you to gain a few pounds, but even that is uncertain.

From Slate ● Jul. 12, 2026

Many of the factors behind these deaths of despair, including addiction, poor diet and stress, also contribute to people spending more of their lives in ill health.

From BBC ● Jul. 12, 2026

Experts, however, advise moderation — saying that regular old water and a balanced diet generally suffice against a backdrop of wellness shortcuts and health hacks.

From MarketWatch ● Jul. 11, 2026

The diet increased healthspan, reduced body fat, and lowered frailty in older mice.

From Science Daily ● Jul. 10, 2026

What he needed was a book that gave him information about its origins, its diet, its weaknesses.

From "Beasts of Prey" by Ayana Gray

And the most robust studies—randomized trials where people are given either “ultra” processed or less processed diets to eat—show few negative impacts.

From Slate ● Jul. 12, 2026

Brits are choosing to prioritise wellness as they become more aware of the risks of poor diets and sedentary health, external, global market insights provider Innova claimed.

From BBC ● Jul. 12, 2026

For example, most of the UPF diets provided in these studies have higher energy density—meaning more calories per bite of food—which is known to cause people to gain a bit of weight.

From Slate ● Jul. 12, 2026

According to Longo, these differences remained even though people with the highest animal protein intake generally consumed fewer calories and otherwise had healthier diets.

From Science Daily ● Jul. 10, 2026

Each time someone discussed anticancer diets or snorting ground-up shark fin or whatever, he’d glance over at me and sigh ever so slightly.

From "The Fault in Our Stars" by John Green

“I just couldn’t look like that no matter how much I dieted or went to the gym.”

From The Wall Street Journal ● May 4, 2026

“Apartments without dining rooms, as if anticipating a future where families disintegrated, compulsively dieted, or ate alone, in front of televisions.”

From Los Angeles Times ● May 15, 2024

For example, one study revealed that compared with daughters of nondieting women, 5-year-old girls whose mothers dieted were aware of the connection between dieting and thinness.

From Salon ● Feb. 22, 2024

The sales rep said: "I yo-yo dieted my whole life, for 30 years, and I got my sleeve two years ago."

From BBC ● Jan. 15, 2024

He dieted on eggs and cottage cheese three or four times a year.

From "The Great Santini" by Pat Conroy

The loss of lean tissue is similar to weight loss from dieting, but the magnitude over a short period can lead to frailty, instability and lack of coordination, doctors and researchers say.

From The Wall Street Journal ● May 17, 2026

Many weight loss programs encourage people to walk more each day, but researchers say there has been limited evidence showing whether increasing daily steps actually helps people lose weight while dieting.

From Science Daily ● May 11, 2026

Interestingly, walking more was not linked to greater weight loss during the initial dieting phase.

From Science Daily ● May 11, 2026

Compared to giving people traditional advice on dieting, such as reducing calorie intake and eating more healthily, the review found intermittent fasting made little to no difference to people's weight loss or quality of life.

From BBC ● Feb. 16, 2026

She was always dieting, and I was always telling her not to.

From "Long Walk to Freedom" by Nelson Mandela