Fad diets are recognized as the worst for the climate

A new study compares the carbon footprint of different eating models.

According to research, the ketogenic diet produces the most greenhouse gases per 1,000 calories (2.9 kg). Additionally harmful to the environment is the paleo diet. A vegan or vegetarian diet is linked to the least amount of greenhouse gas emissions.

Researchers from Tulane University in New Orleans compared the carbon footprint of the six most popular diets in the US. The worst diets in terms of impact on greenhouse gas emissions were the ketogenic diet and the paleo diet, while plant-based diets were the best in terms of climate impact. This suggests that to eat healthy without destroying the planet, we should all eat more plant-based foods.

Carbon footprint comparison of six popular diets—a new study

Nutrition is an important part of figuring out how good a diet is for the environment because it has a big effect on greenhouse gas emissions.

Model diets assume adherence to macronutrients and recommendations, but nutrition does not look like that in practice.

Scientists from New Orleans collected data from 16,6 US residents to compare the carbon footprint of different nutritional models.

  • keto diet,
  • paleo diet,
  • pescatarian diet,
  • vegan diet,
  • vegetarian diet,
  • diet of “omnivores”—without exclusions and restrictions.

Researchers calculated the CO2 emissions of a diet per 1000 kcal to measure its contribution to greenhouse gas emissions.

Carbon footprint of individual diets per kg of CO2 emissions for every 1000 kcal:

  • ketogenic diet: 2.91 kg CO2 per 1000 kcal;
  • paleo diet: 2.6 kg CO2/1000 kcal;
  • Omnivore diet: 2.23 kg/1000 kcal;
  • pescatarian diet: 1.66 kg/1000 kcal;
  • vegetarian diet: 1.16 kg/1000 kcal;
  • vegan diet: 0.7 kg/1000 kcal;

The worst and best diets for the climate

The ketogenic diet was recognized as the worst diet in terms of impact on CO emissions due to its high amount of meat, fish, fat, and cereal carbohydrates. The paleo diet, also known as the diet of our ancestors, has more carbohydrates and focuses on making the products less processed, but it contributes to a significant emission of CO2.

People on plant-based diets reduce greenhouse gas emissions by reducing meat and animal products, which can be seen in the carbon footprint of their menus.

The best diet for climate vs. the best diet for health

The table below shows the classification of diets from worst to best in terms of carbon emissions and health effects.

ClassificationImpact on CO2 emissions (from largest to smallest)Health effects (from worst to best)
1Ketogenic dietKetogenic diet
2Paleo dietPaleo diet
3Omnivores dietOmnivores diet
4Pescarian dietvegan diet
5vegetarian dietvegetarian diet
6vegan dietPescarian diet

As you can see, a good compromise between the healthiness of the diet and its impact on the climate is the use of plant-based diets with the addition of fish and seafood.


O’Malley K., Willits-Smith A., and Rose D. Popular diets as selected by adults in the United States show wide variation in carbon footprints and diet quality. Am J Clin Nutr. 2023 Feb 20:S0002-9165(23)00511-7. doi: 10.1016/j.ajcnut.2023.01.009.

“Modna Dieta Uznana Za Najgorszą Dla Klimatu. Nowe Badanie Porównuje Ślad Węglowy Różnych Modeli Odżywiania – Polki.pl.” Polki.pl, 10 Mar. 2023, polki.pl/dieta-i-fitness/zdrowe-odzywianie,dieta-a-emisja-gazow-cieplarnianych-i-ekologia-porownanie-sladu-weglowego-6-popularnych-diet,10449863,artykul.html.


Keto flu is not contagious, but it can make life miserable. How to deal with it?

Keto flu occurs in some individuals who begin the ketogenic diet. Unquestionably, it is related to a sudden reduction in the amount of carbohydrates in the diet and the body’s entry into ketosis. This is a challenging time when he or she must transition from obtaining energy from carbohydrates to fat. The duration of the keto flu varies, but is typically around seven days.

see also : What is a ketogenic diet? How to do it? When it is better to avoid?

what is keto flue?
Photo by Mateusz Feliksik on Pexels.com

Are you planning to follow a ketogenic diet and concerned about developing keto flu? You need not be overly concerned because it does not affect everyone. In addition, you can reduce the likelihood of its occurrence by acting in a manner that facilitates the body’s adaptation to the new diet. Those who previously consumed a great deal of carbohydrates and sugars and then abruptly adopted the ketogenic diet have the highest risk of developing this condition.

What is the keto flu?

The keto flu is a group of symptoms that can happen 2–7 days after starting the ketogenic diet. Keto flu is not a disease, and doctors have never described or researched it. This doesn’t change the fact that there are a lot of stories on the Internet about people who got the so-called “keto flu” after going on a low-carbohydrate diet.

We don’t know how the keto flu happens, and we don’t even know if it’s a specific set of symptoms because similar ones can happen when people switch to, say, an elimination diet or an anti-inflammatory diet or when they stop eating a lot of highly processed foods.

Not everyone who follows the ketogenic diet gets the keto flu. No one knows why some people have it and others don’t. We don’t know if it’s an immune reaction, a change in the microbiome of the intestines, or a shock after a sudden stop of carbohydrates. Ketoflu is not caused by pathogenic microorganisms, and it is not contagious or dangerous to your health or life.

Keto flu: symptoms

Not everyone has the full set of symptoms that are attributed to the keto flu. Some people notice only a few of the following symptoms :

  • stomach pain,
  • constipation or diarrhoea
  • nausea and vomiting
  • muscle and joint pain ,
  • headaches , including migraines,
  • insomnia or excessive sleepiness
  • fatigue and apathy ,
  • mood swings,
  • involuntary muscle contractions,
  • problems with concentration , memory, and logical thinking.

Many of them are like the flu or stomach flu, but the keto flu has nothing to do with the real flu, which is caused by a virus.

Keto flu: sore throat, fever, and chills

These signs don’t appear because you’re following the keto diet and aren’t its result. This doesn’t mean that some people won’t get keto flu during keto flu, but if they do, it will mean that they also have a bacterial or viral infection, which is a separate problem.

The changes in the body that happen when you drastically cut out carbohydrates and eat more fat and protein are not what cause a sore throat, fever, or chills.

How long does the keto flu last?

It usually lasts about a week, but everyone is different, and we don’t know what makes the symptoms of the keto flu last as long as they do. Some people get better and get rid of them quickly, like in 4 days, while others have to deal with them for up to a month. The good news is that they go away on their own in the long run.

Keto flu: what to do?

Since keto flu is not a disease entity, there are no official guidelines on how to deal with it. Therefore, most often the whole “treatment” consists in the temporary alleviation of symptoms.

However, it is best to try to prevent it by doing the following:

  • Switch to the keto diet gradually, not overnight,
  • take care of proper hydration of the body ,
  • Do not drastically reduce the amount of salt in the diet; the keto diet “flushes” it (electrolytes will ensure hydration and supply of mineral salts).
  • Do not avoid fat in the initial phase of the diet; it is from it that the body will draw energy before it adapts to drawing more from its own adipose tissue.
  • Eat often but in smaller portions.
  • rest ,
  • give up coffee and alcohol.

Most of these tips are worth implementing when keto flu symptoms appear. In the case of severe headaches or muscle and joint pain, they can be temporarily relieved with commonly available painkillers . If you feel very unwell, you should contact your doctor, as it may be the result not only of switching to the keto diet but also of infection.

%d bloggers like this: