Consequences for the body

This is what happens when you eat vegan – after 7, 30 and 365 days

Sunday, 07.01.2024 | 09:10

Every year in January, the British organization “Veganuary” calls for a vegan month – meat, fish and dairy products are taboo. Most people take part for health reasons. What changes do a plant-based diet make in the body?

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Anyone who wants to eat vegan in the long term needs to know how. Inadequate preparation can lead to nutritional deficiencies. That’s why it’s important to get comprehensive information before changing your diet.

One month vegan – for the sake of health

The British organization “Veganuary,” which calls on people to avoid all meat, fish and dairy products in January, takes its participants completely by the hand: for 31 days, they are provided with recipes and tips on veganism by email.

And it’s working: According to the organization, 700,000 people took part in the campaign last year. “And those are just those who officially registered for Veganuary through our website. Opinion research data shows that actual participation in Veganuary is significantly higher,” said a spokesperson.

German meat consumption

  • According to the Federal Office for Agriculture and Food, Germans’ annual per capita meat consumption in 2021 was 52 kilos. This represents a decrease of around 4.2 kilos and is lower than ever before.
  • According to the Federal Nutrition Report 2022, a quarter (25 percent) of Germans eat meat every day – also a decrease compared to previous years. 44 percent of those surveyed follow a flexitarian diet, i.e. they eat meat occasionally, but consciously avoid it from time to time. Another 7 percent are vegetarian and 1 percent are vegan.

Vegan nutrition is still controversial in research

However, researchers disagree about the health consequences of a vegan diet.


The US Academy of Nutrition and Dietetics considers a “well-planned” vegan diet to be “appropriate” and “helpful” at all stages of life – it can have a preventive effect on cardiovascular diseases, type 2 diabetes, high blood pressure, various types of cancer and obesity.

“Professional societies in other countries (e.g. Australia, Canada, Portugal) follow this assessment,” writes the German Nutrition Society (DGE) – but is reluctant to make a recommendation itself; the risk of nutrient deficiencies is too great.

More on the subject of renunciation:

“Anyone who still wants to follow a vegan diet should take a vitamin B12 supplement on a permanent basis, ensure that they consume sufficient amounts of the critical nutrients in particular, and, if necessary, use fortified foods and nutrient supplements,” explains the DGE on its website.

Furthermore, vegans should have their blood values ​​checked regularly. However, the DGE nutrition experts strictly advise against a purely plant-based diet for pregnant women, breastfeeding women, infants, children and adolescents.

What happens in the body – after a week, a month, a year?

What does abstinence from meat, fish and dairy products really do? How long does abstinence have to last until a noticeable change occurs? What happens after a week, a month, a year?

FOCUS Online spoke to two experts: Diana Rubin from the German Society for Nutritional Medicine (DGEM) and Petra Bracht, a specialist in general and nutritional medicine in Bad Homburg.

About the expert

Diana Rubin heads the Vivantes Center for Nutritional Medicine in Berlin-Reinickendorf. The nutrition expert is also on the board of the “German Society for Nutritional Medicine” and heads the Nutrition Committee of the “German Diabetes Society”.

About the expert

Petra Bracht has been a general practitioner and naturopath for more than thirty years. She specializes in nutritional medicine and has seen in her practice for many years how people become healthy through intermittent fasting. In her book
In “Intermittent fasting: For a long life – slim and healthy” (advertisement) she focuses on the health effects of intermittent fasting.

After a week of vegan diet

More awareness: Switching to a plant-based diet requires a lot of knowledge about food. Someone who decides to eat vegan thinks more about what they eat and, if necessary, draws up a nutrition plan. According to Bracht, the general rule is: “People who eat vegan live more mindfully. They pay close attention to what is on their plate and are more likely to choose high-quality products.”

For the expert, who has been vegan for 30 years, this is a particularly important argument for veganism. Because: “At least 80 percent of illnesses result from poor nutrition. The best investment in our health is the food we give our bodies.”

Better digestion, better sleep: “After just one week, you will feel much more alert and fitter. Your digestion will work better, which will also benefit your sleep,” says Bracht. While digestion for omnivores can take between 24 and a maximum of 72 hours, plant-based foods are digested after six to twelve hours.

Weight loss: “Those who switch to a vegan diet lose weight quickly without having to go hungry. It’s not uncommon to lose one or two kilos on the scales after just the first week,” says the expert. However, this is usually water retention, not fat. “Nevertheless, you simply feel lighter, which in turn has a positive effect on your general well-being.”

More on nutrition

After one month of vegan diet

Better blood values: According to Rubin, the first measurable changes begin after one month. A medical check of the blood values ​​should therefore show: “The LDL cholesterol level drops, as does the blood sugar level. High blood pressure also normalizes due to the high potassium intake in a vegan diet.”

According to Bracht, this means that there is no need to take lipid-lowering medication. Blood pressure medication should also be reduced after the first few weeks in consultation with doctors: “Otherwise, blood pressure will plummet.”

The nutritional doctor adds: “Just like cholesterol levels, uric acid levels decrease and patients with fatty liver disease can be happy about their regression.”

After a year of vegan diet

After a year, the effects on health become more pronounced – provided that vegans keep an eye on their vitamin B12 levels. Because people who lack vitamin B12 have an increased risk of heart attack, stroke and dementia.

Vitamin B12

Vitamin B12 is actually a collective term for various cobalamins, such as hydroxy- and adenosylcobalamin in fish and meat, and methylcobalamin in milk. Vitamin B12 is involved as a coenzyme in various metabolic processes in the body. The problem: the body cannot produce it itself and it is essential for life. The main tasks of vitamin B12:

  • It is involved in cell renewal and blood formation.
  • It stabilizes the DNA.
  • It protects nerves and brain.
  • It supports protein and fat metabolism.
  • Vitamin B12 converts the harmful homocysteine ​​into the less harmful methionine. Homocysteine ​​is an amino acid that damages blood vessels, promotes arteriosclerosis and is linked to heart attacks and strokes.

So what about vitamin B12? Vitamin B12 is the only nutrient that vegans cannot get from their diet, but must supplement on a permanent and consistent basis. However, it can take years for the vitamin B12 stores to be used up, explains Rubin.

For her, however, this is the reason why she would not recommend a vegan diet: “I generally do not advocate nutritional supplements, but vitamin B12 supplementation is essential for vegans. Therefore, I would recommend a vegetarian diet.” Vegetarians absorb vitamin B12 through the consumption of dairy products and eggs.

Vitamin B12 is also supplied to animals through their feed

Vegan Petra Bracht, on the other hand, sees no problem here. Some animals also need to be given vitamin B12 because they do not get enough of it themselves – pigs and poultry, for example: “In their case, vitamin B12 is added to the animal feed, so it is simply supplemented elsewhere.”

She does not understand why this discussion even exists: “So food supplements are bad, while at the same time more and more people have to take cholesterol, high blood pressure or blood sugar lowering drugs because of an unbalanced meat-based diet.”

Instead, she says she has “fantastic blood values,” her body has adjusted to her desired weight, and overall she feels more efficient, more beautiful and therefore more comfortable in her body – an effect that can be seen after just one year of being vegan.


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