# Low carb, keto and Mediterranean diets compared

No diet beats all others. The German guideline sets several side by side as equal options: you may choose what suits you.[^1]

## What the terms mean

| Diet | What it means |
| --- | --- |
| Low carb | No uniform limit. Cochrane names under 45% of energy from carbohydrates or 50 to 150 g a day[^2] |
| Keto | Very few carbohydrates, often 20 to 50 g a day, so that the body makes ketones[^3] |
| Mediterranean | No gram figure but a pattern: lots of plant foods, olive oil or nuts as the fat source, often more whole grains and fish and less meat[^4] |

For comparison: a balanced diet in Cochrane's terms has 45 to 65% carbohydrates.[^2] The DGE names more than 50% for a wholesome mixed diet.[^5]

## What happens to weight

The difference is small. In a Cochrane review of 61 studies, low carb probably made little or no difference compared with balanced diets after one to two years, about 0.9 kg in people without diabetes.[^2]

In a large study of 609 adults, low fat and low carb were 0.7 kg apart after one year, and neither genes nor insulin predicted who did better on what.[^6] An analysis of 121 studies saw similar losses at 6 months, and at 12 months they shrank for all diets.[^7]

Whatever the diet, the S3 guideline expects an average of about 5 to 6 kg after 12 months with a deficit of 500 to 600 kcal a day.[^1]

## What counts in the end

In a study of 160 people, weight loss depended on how well someone stuck with it, not on the diet.[^8] These are links, and people who lose weight may also find it easier to stick with it.

So it pays to ask honestly: could I still eat like this in a year, with family, canteen and holidays? A diet you drop after three weeks does little.

## Heart and health

The Mediterranean diet has the most data on the heart and mortality. The well-known PREDIMED study of 7,447 people was retracted in 2018 because of flaws in allocation and reanalysed. About 30% fewer major cardiovascular events remained.[^9] In an analysis of 40 studies, Mediterranean and low-fat programmes lowered mortality, with no convincing difference between them.[^10] Cochrane is more cautious and sees uncertainty on hard outcomes.[^4]

Such studies are missing for low carb and keto. Observational data show that the source matters: when carbohydrates were replaced by animal fat and protein the risk of death was higher, with plant sources it was lower.[^11] The WHO names no amount of carbohydrates and relies on whole grains, vegetables, fruit and pulses instead.[^12]

On keto, LDL cholesterol can rise. In a small comparison of 33 people it rose by 10% on keto and fell by 5% on a Mediterranean diet.[^13] Have your blood lipids checked if you eat this way for longer.

## Who needs to be careful with keto

- **Diabetes medicines:** With SGLT2 inhibitors, case reports describe a dangerous acidosis after a short time. The product information warns in general about conditions with restricted food intake.[^14][^15]
- **Insulin and type 1 diabetes:** According to the German Diabetes Society this needs close monitoring.[^16]
- **Pregnancy and breastfeeding:** Experts currently advise against it, and the data are thin.[^3][^17]
- **Kidneys and liver:** Keto counts as delicate with advanced disease.[^18]

If you take medicines or have a health condition, talk to your doctor first. The S3 guideline advises against one-sided extreme diets.[^1] More under [When to get medical advice](https://kostenlos-abnehmen.de/en/wissen/aerztlicher-rat).

## Sources

[^1]: [German Obesity Society (DAG): S3 guideline on obesity, AWMF 050-001, version 5.0, 2024](https://register.awmf.org/assets/guidelines/050-001l_S3_Praevention-Therapie-Adipositas_2024-10.pdf)
[^2]: [Naude CE et al.: Low-carbohydrate versus balanced-carbohydrate diets for reducing weight and cardiovascular risk. Cochrane Database Syst Rev, 2022](https://pubmed.ncbi.nlm.nih.gov/35088407/)
[^3]: [Evert AB et al.: Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care, 2019](https://pubmed.ncbi.nlm.nih.gov/31000505/)
[^4]: [Rees K et al.: Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev, 2019](https://pubmed.ncbi.nlm.nih.gov/30864165/)
[^5]: [German Nutrition Society (DGE): Reference values for carbohydrates](https://www.dge.de/wissenschaft/referenzwerte/kohlenhydrate/)
[^6]: [Gardner CD et al.: Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss. JAMA, 2018](https://pubmed.ncbi.nlm.nih.gov/29466592/)
[^7]: [Ge L et al.: Comparison of dietary macronutrient patterns of 14 popular named dietary programmes. BMJ, 2020](https://pubmed.ncbi.nlm.nih.gov/32238384/)
[^8]: [Dansinger ML et al.: Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets. JAMA, 2005](https://pubmed.ncbi.nlm.nih.gov/15632335/)
[^9]: [Estruch R et al.: Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med, 2018](https://pubmed.ncbi.nlm.nih.gov/29897866/)
[^10]: [Karam G et al.: Comparison of seven popular structured dietary programmes and risk of mortality and major cardiovascular events. BMJ, 2023](https://pubmed.ncbi.nlm.nih.gov/36990505/)
[^11]: [Seidelmann SB et al.: Dietary carbohydrate intake and mortality. Lancet Public Health, 2018](https://pubmed.ncbi.nlm.nih.gov/30122560/)
[^12]: [WHO: Carbohydrate intake for adults and children, 2023](https://www.who.int/publications/i/item/9789240073593)
[^13]: [Gardner CD et al.: Effect of a ketogenic diet versus Mediterranean diet on glycated hemoglobin. Am J Clin Nutr, 2022](https://pubmed.ncbi.nlm.nih.gov/35641199/)
[^14]: [Mistry S et al.: Euglycemic Diabetic Ketoacidosis Caused by SGLT2 Inhibitors and a Ketogenic Diet. AACE Clin Case Rep, 2021](https://pubmed.ncbi.nlm.nih.gov/33851013/)
[^15]: [EMA: Forxiga, product information, section 4.4](https://www.ema.europa.eu/en/documents/product-information/forxiga-epar-product-information_en.pdf)
[^16]: [Skurk T et al.: Empfehlungen zur Ernährung von Personen mit Typ-2-Diabetes mellitus. Diabetologie und Stoffwechsel, 2023](https://www.ddg.info/fileadmin/user_upload/05_Behandlung/01_Leitlinien/Praxisempfehlungen/2023/dus_2023_Praxisempfehlungen_Skurk_Ernaehrungstherapie-Typ2.pdf)
[^17]: [Watanabe M et al.: Scientific evidence underlying contraindications to the ketogenic diet. Obes Rev, 2020](https://pubmed.ncbi.nlm.nih.gov/32648647/)
[^18]: [Dyńka D et al.: The ketogenic diet is not for everyone. Ann Med, 2026](https://pubmed.ncbi.nlm.nih.gov/41486865/)

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Last updated: November 2026. This is general information and not medical advice.

Original article: https://kostenlos-abnehmen.de/en/wissen/low-carb-keto-mittelmeer