Keto vs Paleo vs Whole30 vs Atkins: How the Four Diets Compare
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Keto vs paleo vs Whole30 vs Atkins: keto and Atkins are defined by how much carbohydrate you eat, while paleo and Whole30 are defined by which foods you leave out. The British Dietetic Association (BDA) puts ketogenic diets at 20–50g of carbs a day, and Atkins' own plans are set at about 20g, 40g or 100g of net carbs a day. Paleo and Whole30 set no carb target, but both tell you to avoid grains, dairy and legumes. Whole30 is a 30-day programme followed by reintroduction.
At a glance
- 20–50gcarbs a day on a very low carb (ketogenic) diet, according to the BDA
- 20g, 40g or 100gnet carbs a day on Atkins' three plans, as Atkins sets them out
- No carb targeton paleo or Whole30: both are built around which foods to leave out
- 30 daysof elimination on the Original Whole30, then 10 or more days of reintroduction
On this page
Keto vs paleo, Atkins vs keto, paleo vs Whole30: these four diets are often lumped together, but they work on different rules. This guide describes each one by its own rules, from the BDA for keto and from the official Atkins, Paleo Diet and Whole30 websites for the other three. It then sets out what the BDA and the NHS say about cutting carbs and cutting out food groups. It doesn't rank the diets or say which one to follow.
Keto vs paleo vs Whole30 vs Atkins compared
| Diet | Carb rule | Main foods left out | How long |
|---|---|---|---|
| Keto | 20–50g carbs a day (BDA) | Sugary and starchy foods, such as bread, pasta, rice, potatoes and cereal | No set length |
| Atkins | About 20g, 40g or 100g net carbs a day, by plan | Not listed on its plans page; Atkins says "nothing is off the table" on its 100g plan | No set length |
| Paleo | No macronutrient ratios | Dairy, grains, legumes and processed foods; limit added sugar and salt | No set length |
| Whole30 | No counting or tracking food | Added sugar and sweeteners, alcohol, grains, legumes and dairy | 30 days, then 10+ days of reintroduction |
Sources: BDA low carb diets fact sheet (keto); atkins.com (Atkins); thepaleodiet.com (paleo); whole30.com, Original Whole30 rules (Whole30). Checked 3 November 2026.
The keto diet
Keto has no single organisation that sets its rules, so we use the BDA's definition. Its low carb diets fact sheet groups diets by how much carbohydrate they allow a day:
| Type of diet (BDA) | Carbohydrate a day |
|---|---|
| Very low carb (ketogenic) | 20–50g |
| Low carb | 50–130g |
| Moderate carb | 130–220g |
| High carb | more than 225g |
Source: British Dietetic Association, Low carb diets food fact sheet.
The BDA says sugary and starchy foods, including sugar, sweets, chocolate, biscuits, cakes, breakfast cereal, bread, potatoes, pasta, rice and noodles, are generally avoided on a low carb diet. It also lists foods with natural carbohydrate that can be included, such as milk, natural yoghurt, fruit, green leafy vegetables and salad. So unlike paleo and Whole30, keto doesn't rule out dairy as a food group. Our guides to cheese and yoghurt give the carbs per 100g.
The NHS also mentions the ketogenic diet in its epilepsy treatment page. The NHS says medicines work well for most people with epilepsy, and that rarely other treatments are needed. These can include "a specialist diet that can reduce seizures (ketogenic diet)".
The Atkins diet
Atkins' own website (atkins.com, the US site) currently sets out three plans, each with a daily net carb level:
- Atkins KickStart: about 20g of net carbs a day. Atkins calls it "The Original Atkins".
- Atkins Flex: about 40g of net carbs a day, which Atkins describes as ketogenic eating.
- Atkins 100: about 100g of net carbs a day. Atkins says "nothing is off the table" on this plan.
Atkins sets its plans in net carbs. On UK labels, fibre is listed separately and isn't part of the carbohydrate figure, as our guide to net carbs on UK labels shows. So check which kind of figure a recipe or app is using.
Atkins' site also says to consult a doctor or other qualified healthcare provider before starting any new diet, especially if you're pregnant, nursing, have a medical condition or take medicines.
The paleo diet
The Paleo Diet website says its organisation created the diet under its founder, Dr Loren Cordain. It describes the diet as based on what humans ate before organised farming. Its rules are about food types, not amounts:
- Eat: plenty of vegetables and fruits, natural meats and seafood, and some nuts and seeds.
- Avoid: dairy, grains, legumes and processed foods, which it calls the biggest categories to avoid, and "shy away from" added sugar and salt.
- Carbs: it says not to count calories or stress about macronutrient ratios.
- Flexibility: it says most people can eat any foods for up to 15% of meals.
So paleo sets no carb limit by its own rules, and fruit is on its list.
Whole30
The Original Whole30 programme, as set out on whole30.com, has two phases: 30 days of elimination and then 10 or more days of reintroduction. During the 30 days, it says to cut out:
- added sugar, real or artificial, including honey, maple syrup, stevia, erythritol and xylitol (100% fruit juice is the exception)
- alcohol, in any form, including in cooking
- grains, including wheat, oats, rice, corn and pseudo-cereals such as quinoa and buckwheat
- legumes, including beans, lentils, soy and peanuts (green beans and most peas are allowed)
- dairy, apart from clarified butter or ghee
- bread, wraps, pancakes, biscuits and other baked goods, pasta and cereal made with alternative flours, plus crisps and chips (French fries)
It also says not to weigh yourself or take measurements during the 30 days. In the reintroduction phase, food groups are added back one at a time. Whole30 says elimination programmes like it "aren't meant to be followed long-term", and that "your doctor's orders always supersede Whole30 program rules". There's also a separate Plant-Based Whole30, with its own rules.
Because erythritol and stevia are excluded, keto sweeteners don't fit the Original Whole30. Our guide to honey covers another sweetener it leaves out.
Keto vs Atkins
Comparing the BDA's ketogenic band with Atkins' own plans:
- Atkins KickStart (20g) and Atkins Flex (40g) sit inside the BDA's 20–50g very low carb (ketogenic) band.
- Atkins 100 (about 100g) sits in the BDA's low carb band of 50–130g, not the ketogenic one.
- The counting differs. Atkins sets its plans in net carbs, while the BDA bands are given as carbohydrate a day.
Paleo vs Whole30
Paleo and Whole30 overlap more with each other than with keto or Atkins. By their own rules:
- Both avoid grains, dairy and legumes, and neither sets a carb target.
- Whole30 is time-limited: 30 days, then reintroduction. Paleo has no set length.
- Whole30 is stricter on sweeteners and alcohol: it excludes all added sugar and sweeteners and all alcohol, while paleo says to shy away from added sugar.
- Treats differ: The Paleo Diet suggests making treats with honey and almond flour, to be eaten sparingly, and says most people can eat any foods for up to 15% of meals. Whole30 excludes honey and baked goods made with alternative flours.
What UK health bodies say
None of the BDA or NHS pages we checked assesses these four diets side by side. These are the relevant points they do make:
- Cutting carbs: the BDA says studies have shown low carb diets are safe over the short term (up to one year), but there is very little information about the safety of low carb diets over the longer term. It lists concerns about eating less fibre and more red and processed meat and saturated fat, and says few studies have looked at this.
- Pregnancy: the BDA says ketogenic diets should not be followed by women who are pregnant.
- Food groups: the NHS Eatwell Guide divides food into 5 main groups, including starchy foods, dairy and alternatives, and beans, pulses, fish, eggs, meat and other protein foods. Paleo and Whole30 leave out grains, dairy and legumes, and keto and Atkins limit starchy foods.
- Cutting foods out: on food intolerance, the NHS says it's important not to cut foods out of your diet without the advice of a GP or food and nutrition specialist (dietitian), because you could miss out on certain vitamins and minerals.
Speak to your GP, diabetes nurse or a registered dietitian before you make big changes to your diet. This is especially important if you have diabetes and take insulin or other medicines that can cause hypos, or take SGLT2 inhibitors, as your medication may need to change. The same goes if you're pregnant, breastfeeding or have a history of eating disorders.
Key takeaways
- Keto and Atkins are carb-based: 20–50g a day for keto (BDA), and about 20g, 40g or 100g of net carbs a day on Atkins' plans.
- Paleo and Whole30 are food-group based: both leave out grains, dairy and legumes, with no carb target.
- Whole30 lasts 30 days, then reintroduction, and excludes all sweeteners, including erythritol and stevia.
- The BDA and NHS flag less fibre on low carb diets, no ketogenic diets in pregnancy, and advice before cutting foods out.
Frequently asked questions
Is Atkins the same as keto?
Not always. Atkins has three plans: about 20g, 40g or 100g of net carbs a day. The BDA's very low carb (ketogenic) band is 20–50g of carbs a day, so KickStart and Flex fall within it, while Atkins 100 falls in the BDA's 50–130g low carb band. Atkins counts net carbs, though, so the figures aren't measured the same way.
What's the difference between keto and paleo?
Keto is defined by a carb limit, which the BDA puts at 20–50g a day. Paleo, as set out by The Paleo Diet, has no carb target and says not to stress about macronutrient ratios. Instead it leaves out dairy, grains, legumes and processed foods. So keto can include dairy, while paleo sets no carb limit on fruit.
What's the difference between paleo and Whole30?
Both avoid grains, dairy and legumes. Whole30 is a 30-day elimination programme followed by at least 10 days of reintroduction, and it excludes all added sugar and sweeteners, alcohol and baked goods made with alternative flours. Paleo has no set length and says most people can eat any foods for up to 15% of meals.
Can you use keto sweeteners on Whole30?
Not on the Original Whole30. Its rules exclude added sugar, real or artificial, and the list names stevia, erythritol and xylitol, as well as honey and maple syrup. The only exception it gives is 100% fruit juice. Keto bakes made with alternative flours are also excluded under its rules for baked goods.
Can you follow keto and paleo at the same time?
Some people combine the rules of both. By their own definitions, that would mean keeping to the BDA's 20–50g of carbs a day for keto while also leaving out the dairy, grains, legumes and processed foods that The Paleo Diet avoids. Speak to your GP or a dietitian before cutting out several food groups.
Sources
- British Dietetic Association. Low carb diets food fact sheet (carbohydrate bands, foods generally avoided and included, longer-term safety and concerns, pregnancy).
- NHS. Epilepsy: treatment (ketogenic diet as a specialist diet), The Eatwell Guide (5 main food groups) and Food intolerance (not cutting foods out without advice). Checked 3 November 2026.
- Atkins Nutritionals. How it works (Atkins 100, Atkins Flex 40 and Atkins KickStart 20 plans; advice to consult a healthcare provider). Checked 3 November 2026.
- The Paleo Diet. What can you eat on The Paleo Diet? (founder, foods to eat and avoid, macronutrient ratios, treats, 15% of meals). Checked 3 November 2026.
- Whole30. Original Whole30 rules (elimination and reintroduction phases, foods excluded, exceptions, no weighing, not meant long-term, doctor's orders). Checked 3 November 2026.
