Keto, low-carb and Atkins all cut carbohydrates, but by different amounts and with different rules. A ketogenic diet keeps carbs very low, usually 20 to 50 g of net carbs a day, so the body makes ketones from fat. A general low-carb diet is more flexible, often 50 to 130 g of carbs a day, and doesn’t aim for ketosis. Atkins is a branded low-carb plan that starts very low, similar to keto, then adds carbs back in stages to find your personal limit. For weight loss, the research suggests they work about as well as each other, and as well as other diets, so the best one is the version you can stick to and that suits your health.
Keto vs low carb vs Atkins at a glance
| Keto | Low carb | Atkins | |
|---|---|---|---|
| Daily carbs | About 20 to 50 g net carbs | About 50 to 130 g | Starts at about 20 to 25 g net carbs, then increases in phases |
| Goal | Stay in ketosis | Reduce refined carbs and sugar | Lose weight, then find a carb level you can maintain |
| Fat | High, often 60 to 75% of calories | Moderate to high | Moderate to high |
| Protein | Moderate | Moderate to high | Moderate to high |
| Fruit and whole grains | Very limited | Some allowed | Gradually reintroduced |
| Flexibility | Low | High | Medium, changes over time |
| Best known for | Rapid early weight loss, medical uses such as epilepsy | Sustainable everyday eating | Structured phases |
What is a ketogenic diet?
A ketogenic diet cuts carbohydrate so far that your body switches to using fat and ketones as its main fuel. Most people need to stay under about 20 to 50 g of net carbs a day. Typical foods include meat, fish, eggs, cheese, non-starchy vegetables, nuts, seeds, avocado and oils, with very little fruit, grains, beans or starchy vegetables. Our keto diet food list and guide to keto macros explain the details.
What is a low-carb diet?
“Low carb” is a broad term for any diet that eats noticeably fewer carbs than usual, typically by cutting sugar, refined grains and sugary drinks while keeping some whole grains, fruit, beans and starchy vegetables in moderation. It’s more flexible than keto and doesn’t require ketosis. Many people find it easier to follow long term.
What is the Atkins diet?
Atkins is a commercial low-carb plan created by Dr Robert Atkins. It’s typically structured in phases:
- Induction: very low carbs, around 20 to 25 g of net carbs a day, similar to keto.
- Balancing: gradually adding nuts, seeds, berries and more vegetables.
- Fine-tuning: adding more carbs until weight loss slows, to find your limit.
- Maintenance: eating at your personal carb level long term.
There are also versions that start with more carbs.
Which works best for weight loss?
All three can help you lose weight, mainly by helping you eat fewer calories, often without counting. In the DIETFITS trial, people on a healthy low-carb diet and those on a healthy low-fat diet lost similar amounts of weight after 12 months. A meta-analysis of trials lasting at least a year found that very low-carb diets led to slightly more weight loss than low-fat diets, by less than 1 kg on average. The small differences between diets matter less than how consistently you can follow them. Our comparison of keto vs calorie counting explains more.
Health considerations
- Blood sugar: cutting refined carbs often improves blood sugar control, which can help people with type 2 diabetes, but medicines may need adjusting. Talk to your doctor before starting.
- Cholesterol: LDL cholesterol rises in some people on keto and very low-carb diets, especially with lots of saturated fat. Our guide to keto and cholesterol explains what to watch.
- Fiber and nutrients: stricter diets make it harder to get enough fiber, vitamin C, magnesium and folate. Our guide to nutrient deficiencies on keto has tips.
- Food quality: a low-carb diet based on vegetables, fish, eggs, nuts and olive oil is very different from one based on processed meat and cheese.
How to choose
- Choose keto if you want clear rules, find it easy to give up most carbs, or have a medical reason under supervision.
- Choose a moderate low-carb diet if you want flexibility and to keep some fruit, beans and whole grains.
- Consider an Atkins-style approach if you like the structure of starting low and then adding carbs back gradually.
- Consider a Mediterranean diet if heart health is your main goal; it has strong evidence and can be adapted to lower carbs. Our guide to Mediterranean keto combines the two.
A day of eating on each plan
| Meal | Keto | Low carb | Atkins (later phases) |
|---|---|---|---|
| Breakfast | Eggs fried in butter with spinach and avocado | Greek yogurt with berries and a handful of nuts | Cheese and pepper omelet with a few strawberries |
| Lunch | Chicken salad with olive oil, olives and feta | Lentil and vegetable soup with a small whole grain roll | Tuna salad with mixed leaves, tomatoes and seeds |
| Snack | A few macadamias or a piece of cheese | An apple with peanut butter | Celery with cream cheese |
| Dinner | Salmon with roasted zucchini and garlic butter | Chicken stir-fry with vegetables and a small portion of brown rice | Steak with broccoli, cauliflower mash and a small serving of beans |
| Rough carb total | 20 to 30 g | 80 to 120 g | 40 to 80 g |
Which is easiest to stick with?
Strictness and staying power tend to pull in opposite directions. Keto’s clear rules suit some people, but many find it hard to keep up at work events, holidays and family meals. A moderate low-carb diet leaves room for fruit, beans and whole grains, which also makes it easier to get enough fiber. Atkins sits in between, with strict early weeks and a looser long-term phase. If you’ve tried keto and kept slipping, a more moderate approach may be the more realistic long-term plan, and it still cuts out most sugar and refined starch.
Common questions
Is Atkins the same as keto?
Not exactly. Atkins starts with a keto-like phase but gradually adds carbs, while keto keeps carbs very low throughout.
Can I switch from keto to low carb?
Yes. Many people use keto to start and move to a more flexible low-carb diet for the long term. Add carbs gradually, choosing fiber-rich foods first.
How many carbs is “low carb”?
There’s no single definition, but under about 130 g a day is often used, compared with around 200 to 300 g in a typical diet.
Which is best for type 2 diabetes?
Lower-carb eating can improve blood sugar in type 2 diabetes, but the right level of carbs varies from person to person, and medicines may need changing as you cut carbs. Plan any change with your diabetes team. Our guide to keto and type 2 diabetes explains the risks.
Safety note: Keto isn’t suitable for everyone. If you have diabetes, kidney or liver disease, take regular medication, or are pregnant or breastfeeding, talk to your doctor before cutting carbs this far (why it matters).
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
