Body changes after going vegetarian

Vowing to ditch steaks and burgers in favour of a vegetarian lifestyle may have crossed your mind for ethical reasons or because of concerns about red meat and health.

So, what actually happens to your body when you stop eating meat?

You lose weight

A team at George Washington University School of Medicine in Washington in the US recently tried pinpoint how much weight a person loses if they switch from being an omnivore to a vegetarian.

The research, which reviewed previous studies and was published in the Journal of the Academy of Nutrition and Dietetics, showed particpants who cut meat out of their diets lost around 10lbs on average without monitoring their calorie intake or increasing the amount they exercised.

“The take-home message is that a plant-based diet can help you lose weight without counting calories and without ramping up your exercise routine,” Neal Barnard, M.D., lead author of the study and an adjunct associate professor of medicine at the George Washington University, said at the time.

Your gut bacteria will change

The saying goes you are what you eat, and that relates to your digestive system as much as any other part of your body.

A 2014 study exploring the difference between the gut bacteria found in omnivores, vegans and vegetarians found differences in all three.

However, the biggest variation was between omnivorese and vegans – who don’t consume any animal products whatsoever.

Researchers at City University of New York found that vegans had more protective species of gut bacteria.

You could become deficient in nutrients

A balanced vegetarian or vegan diet can provide enough nutrients with enough planning. But it can be harder to get enough iron, vitamin D and vitamin B12, according to the NHS.

The body recommends eating enough pulses, such as beans and lentils, nuts, fruit, dark green vegetables, wholegrains, and cereals with fortified irons to get enough of the substance.

Vegetarian diet
Vegetarian diet

Vitamin B12 can meanwhile be found in yeast extract products such as Marmite, fortified breakfast cereals, and soya products.

Eggs, fortified fat spreads, cereals and some milks can be a source of vitamin D.




Your risk of developing cancer could drop…

A recent World Health Organisation report classed processed meat as carcinogenic, and so products such as bacon and salami found themselves categorised alongside formaldehyde, gamma radiation and cigarettes. Red meat was also labelled as “probably” having cancer causing properties.

Eating just a 50g portion of processed meat – or two rashers of bacon a day – increases the risk of bowel cancer by 18 per cent, the experts concluded.

However, while this sounds like a significant rise, the 18-per cent rise in the risk of bowel cancer the IARC scientists warned of is from the base level that around 6 in every 100 people in the UK will get bowel cancer – not in total for each person.

Therefore, the rise would translate to one extra case of bowel cancer in all those 100 lifetime bacon-eaters.

…as well as your chance of having heart disease

Scientists recently found that red meat is linked to heart disease. A study be Lerner Research Institute in the US showed that carnitine, a nutrient found in the food, sets of gut microbe reactions which contribute to the development of heart disease.

Processed meats cause cancer

Processed meats – such as bacon, sausages and ham – do cause cancer, according to the World Health Organization (WHO).

Its report said 50g of processed meat a day – less than two slices of bacon – increased the chance of developing colorectal cancer by 18%.

Meanwhile, it said red meats were “probably carcinogenic” but there was limited evidence.

The WHO did stress that meat also had health benefits.

Cancer Research UK said this was a reason to cut down rather than give up red and processed meats.

And added that an occasional bacon sandwich would do little harm.

Processed meat has been modified to either extend its shelf life or change the taste and the main methods are smoking, curing, or adding salt or preservatives.

Simply putting beef through a mincer does not mean the resulting mince is “processed” unless it is modified further.

Processed meat includes bacon, sausages, hot dogs, salami, corned beef, beef jerky and ham as well as canned meat and meat-based sauces.

It is the chemicals involved in the processing which could be increasing the risk of cancer. High temperature cooking, such as on a barbeque, can also create carcinogenic chemicals.

In the UK, around six out of every 100 people get bowel cancer at some point in their lives.

If they were all given an extra 50g of bacon a day for the rest of their lives then the risk would increase by 18% to around seven in 100 people getting bowel cancer.

“So that’s one extra case of bowel cancer in all those 100 lifetime bacon-eaters,” argued Sir David Spiegelhalter, a risk professor from the University of Cambridge.

The WHO has come to the conclusion on the advice of its International Agency for Research on Cancer, which assesses the best available scientific evidence.

It has now placed processed meat in the same category as plutonium, but also alcohol as they definitely do cause cancer.

Processed meats
Processed meats

However, this does not mean they are equally dangerous. A bacon sandwich is not as bad as smoking.

“For an individual, the risk of developing colorectal (bowel) cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” Dr Kurt Straif from the WHO said.

That is in contrast to one million deaths from cancer caused by smoking and 600,000 attributed to alcohol each year.

Red meat does have nutritional value too and is a major source of iron, zinc and vitamin B12.

However, the WHO said there was limited evidence that 100g of red meat a day increased the risk of cancer by 17%.




An eight ounce steak is 225g.

Prof Tim Key, from the Cancer Research UK and the University of Oxford, said: “This decision doesn’t mean you need to stop eating any red and processed meat, but if you eat lots of it you may want to think about cutting down.

“Eating a bacon bap every once in a while isn’t going to do much harm – having a healthy diet is all about moderation.”

Dr Teresa Norat, one of the advisors to the WHO report and from Imperial College London, said there were many factors causing bowel cancer.

She told BBC News website: “People should limit consumption of red meat and avoid consuming processed meat, but they should also have a diet rich in fibre, from fruit and vegetables and maintain an adequate body weight throughout life and limit the consumption of alcohol and be physically active.”

The industry body the Meat Advisory Panel said “avoiding red meat in the diet is not a protective strategy against cancer” and said the focus should be alcohol, smoking and body weight.