Subtotal $0.00
Shop Now
A whole foods diet is an eating pattern built mostly from foods that are still close to how they grow or are raised: vegetables, fruits, beans, lentils, whole grains, nuts, seeds, eggs, fish, meat and plain dairy, with fewer packaged, highly processed products. It is an informal term, not a diet with an official definition, rules or a governing body, so versions differ. Some include animal foods; a whole food plant-based diet leaves most or all of them out. This guide explains what is a whole foods diet in practice, how researchers sort foods by processing with the NOVA system, what the US Dietary Guidelines say, and what one well-known NIH feeding trial did and did not show.
Peptide Labs does not sell whole foods or meal programs. This article is general nutrition information, not medical advice. If you have a medical condition, take medicines, are pregnant, or have a history of disordered eating, talk with a clinician or registered dietitian before changing how you eat.
Key Takeaways
- A whole foods diet has no official definition; it usually means eating mostly unprocessed or minimally processed foods.
- The NOVA system sorts foods into four groups by the extent and purpose of processing, from fresh foods to ultra-processed products.
- The 2025-2030 Dietary Guidelines tell Americans to prioritize whole, nutrient-dense foods and limit highly processed foods, without giving a formal definition of that term.
- A 2019 NIH inpatient trial in 20 adults found people ate about 500 more calories a day on an ultra-processed diet than on an unprocessed one; it was small and lasted four weeks in total.
- A whole food plant-based diet can be nutritionally adequate when planned well, but vitamin B12 needs a reliable source such as fortified foods or supplements.
What is a whole foods diet?
Most descriptions of a whole foods diet share one idea: choose the food itself more often than a product made from it. An apple instead of apple-flavored snacks, oats instead of a sweetened cereal bar, a chicken breast instead of breaded nuggets, dried beans or lentils instead of a boxed side dish. Processing is not all-or-nothing, and many whole-food eaters still use olive oil, plain yogurt, frozen vegetables, canned beans and bread from a bakery.
Because nobody owns the term, there is no list of approved and banned foods. That flexibility is useful, but it also means claims attached to the label vary a lot. A diet called whole foods can be high or low in fiber, salt or saturated fat depending on which foods fill the plate. The overall pattern matters more than the name, which is why eating patterns such as the Mediterranean diet or a flexitarian diet overlap heavily with whole-food eating.
How the NOVA system sorts foods by processing
Researchers who study processing often use NOVA, a classification created in Brazil in 2010 that groups foods by the nature, extent and purpose of industrial processing rather than by nutrients, according to peer-reviewed papers by its developers in Public Health Nutrition (2018 and 2019) and a 2025 essay in the Brazilian Journal of Epidemiology. Its four groups are summarized below.
| NOVA group | What it covers | Examples given by NOVA authors |
|---|---|---|
| 1. Unprocessed or minimally processed foods | Edible parts of plants or animals, changed only by steps such as drying, milling, freezing or pasteurizing, with no added salt, sugar, oils or fats | Fresh or frozen fruit and vegetables, grains, legumes, eggs, milk, plain yogurt, meat, fish |
| 2. Processed culinary ingredients | Substances pressed, refined or extracted from group 1 foods or from nature, used in cooking | Vegetable oils, sugar, honey, vinegar, salt, butter, lard |
| 3. Processed foods | Group 1 foods with group 2 ingredients added, often by canning, bottling or baking | Vegetables or pulses canned in brine, salted nuts, cheeses, breads |
| 4. Ultra-processed foods | Industrial formulations, mostly of substances extracted from foods plus additives | Products whose ingredient list includes items such as high-fructose corn syrup, hydrogenated oils or cosmetic additives |
The 2019 NOVA paper offers a practical shortcut: a product is likely ultra-processed if its ingredient list contains at least one substance rarely used in home kitchens, such as high-fructose corn syrup, hydrogenated or interesterified oils or hydrolysed proteins, or additive classes meant to make food more appealing, such as flavors, colors like Red Dye 40, emulsifiers, sweeteners and thickeners. NOVA describes processing, not nutrient content, so it is one lens among several.
What the Dietary Guidelines say about processed foods
The 2020-2025 Dietary Guidelines for Americans described nutrient-dense foods as those that provide vitamins, minerals and other health-promoting components with little added sugars, saturated fat and sodium, naming vegetables, fruits, whole grains, seafood, eggs, beans, peas, lentils, unsalted nuts and seeds, fat-free and low-fat dairy, and lean meats and poultry when prepared with little added sugar, saturated fat or sodium.
The 2025-2030 Dietary Guidelines open with the message to eat real food and tell households to prioritize diets built on whole, nutrient-dense foods with a sharp reduction in highly processed foods. Specific lines include:
- Avoid highly processed packaged, prepared or ready-to-eat foods that are salty or sweet, such as chips, cookies and candy, and prioritize nutrient-dense foods and home-prepared meals.
- Limit foods and drinks with artificial flavors, petroleum-based dyes, artificial preservatives and low-calorie non-nutritive sweeteners.
- Significantly reduce highly processed refined carbohydrates such as white bread, packaged breakfast options, flour tortillas and crackers; our refined carbohydrates guide covers the details.
- Avoid highly processed foods that are high in sodium; see our guide to lower-sodium foods.
The 2025-2030 document uses the phrase highly processed foods with examples but does not give a formal definition, and it is not the same thing as the NOVA ultra-processed group. A label or website calling a product whole food is a marketing description, not a regulated claim defined in these Guidelines.
The NIH ultra-processed diet trial, reported accurately
The study cited most often in whole-food discussions is a randomized crossover trial by Kevin Hall and colleagues at the National Institutes of Health, published in Cell Metabolism in 2019. Twenty weight-stable adults lived at the NIH Clinical Center and ate an ultra-processed diet for 2 weeks and an unprocessed diet for 2 weeks, in random sequence. The meals offered were matched for calories, energy density, macronutrients, sugar, sodium and fiber, and participants could eat as much or as little as they wanted.
On the ultra-processed diet, people ate about 508 more calories a day on average, mostly from extra carbohydrate and fat rather than protein. Body weight tracked intake: participants gained about 0.9 kg during the ultra-processed phase and lost about 0.9 kg during the unprocessed phase.
Limits matter. The trial had 20 people, each phase lasted two weeks, food was prepared and served in a research ward, and the design could not show which feature of ultra-processed food drove the extra eating. It shows what happened under those conditions, not what a whole foods diet will do for any one person at home over months or years.
The whole food plant-based diet
A whole food plant-based diet applies the same idea to a mostly or fully plant-based menu: vegetables, fruits, lentils and other legumes, whole grains such as oats, nuts and seeds, with little or no meat, dairy, eggs or refined products. Like the broader term, it has no official definition.
The Academy of Nutrition and Dietetics states in its 2016 position paper that appropriately planned vegetarian, including vegan, diets are healthful and nutritionally adequate and are appropriate for all stages of life, and that vegans need reliable sources of vitamin B12 such as fortified foods or supplements; our B12 foods guide lists sources. The 2025-2030 Dietary Guidelines add that vegan diets show broader nutrient shortfalls, including vitamins A, D, E, B6 and B12, calcium, iron and zinc, recommend periodic monitoring of nutrient status, and advise significantly limiting highly processed vegan or vegetarian products.
Building meals from whole foods
These are general, plain-language ideas, not a plan with amounts. Needs differ by age, activity, health and budget.
- Start from a vegetable, a legume or a whole grain and add a protein food, rather than starting from a box or a mix.
- Frozen fruit and vegetables without sauces or added sugar count as minimally processed in NOVA and keep well.
- Canned beans and vegetables fall into NOVA’s processed group when salt is added; choosing no-salt-added cans is an option, and the Nutrition Facts panel shows the sodium.
- Read the ingredient list as well as the Nutrition Facts panel; a short list of recognizable foods is a simple signal.
- Plain yogurt, unsalted nuts and seeds, and whole fruit are easy snacks; our high-fiber foods list gives USDA fiber values.
- Nuts, seeds and vegetable oils are also where most vitamin E comes from; see our vitamin E food list.
When personal advice is the safer route
The 2025-2030 Guidelines tell people with chronic disease to work with a health care professional to find a diet appropriate for them. The same applies if you are pregnant or breastfeeding, feeding young children, managing a condition with diet and medicine, or have a history of an eating disorder. A registered dietitian can adapt the idea of whole-food eating to your situation without turning it into a list of forbidden foods.
Frequently Asked Questions
What is a whole foods diet?
An informal eating pattern built mostly from unprocessed or minimally processed foods such as vegetables, fruits, legumes, whole grains, nuts, seeds and, in many versions, eggs, fish, meat and plain dairy. It has no official definition.
Is a whole foods diet the same as a whole food plant-based diet?
Not quite. A whole food plant-based diet is a version that leaves out most or all animal foods, while a general whole foods diet may include them.
Are frozen or canned foods allowed on a whole foods diet?
Most versions include them. NOVA counts plain frozen produce as minimally processed, and canned vegetables or beans with added salt as processed foods, not ultra-processed.
What did the NIH ultra-processed food study find?
In 20 adults living at the NIH Clinical Center, people ate about 508 more calories a day on an ultra-processed diet than on an unprocessed diet matched for offered nutrients. It was a small, short trial.
Do the Dietary Guidelines recommend a whole foods diet?
They do not use that name, but the 2025-2030 edition tells Americans to prioritize whole, nutrient-dense foods and limit highly processed foods.
Do I need supplements on a whole food plant-based diet?
The Academy of Nutrition and Dietetics says vegans need a reliable vitamin B12 source such as fortified foods or supplements. Ask a clinician or dietitian about other nutrients.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Foods High in Vitamin E: USDA Values, Daily Value and Sources, Clean Eating: What It Means, Foods and What Research Says, Mediterranean Diet: What It Is, Food List and What the Research Shows.