This blog is not medical advice and should not be used for that purpose.
6 Simple Steps to a Healthy Life:
Don’t smoke
Don’t drink alcohol excessively
Exercise
Eat fruit and vegetables daily
Choose a way of eating that you enjoy and which helps you reach and maintain a healthy body weight
Don’t focus all of your time and energy on one particular food
An individual’s dietary pattern may be more relevant than a direct effect from a single component (1). This is taken from the Australian Dietary Guidelines and it’s a perfect place to start. Health is more than one particular food, it is all of your lifestyle factors and choices combined.
Much of the talk around meat vs plants comes from observational, population level nutrition studies.
Observational studies can give associations and correlations but not causation. For example, an observational study may question a large group of people about their dietary habits over the past decade. Some correlations may then be able to be formed, such as those who drink soft drink are more likely to be scared of spiders (I made this up, but there are some really funny correlations if you check out this site https://www.tylervigen.com/spurious-correlations).
Correlations are great for directing further, more controlled study to try and prove or disprove causation - the reason things happen.
When taking these observational studies and looking at meat eaters versus non-meat eaters, the vegetarian and vegan populations regularly fare better in terms of correlations towards health outcomes, specifically mortality (2). The obvious counter-arguments for this are that overall, non-meat eaters may be more health-seeking, more health conscious people. They tend to smoke less, drink less (3), exercise more and eat more fiber (4).
So what happens when health seeking meat eaters, who are conscious of smoking, alcohol consumption and exercise, are compared to vegetarians and vegans?
Turns out there doesn’t appear to be any difference between health seeking meat eaters and health seeking vegetarians, vegans, pescatarians or once per week meat eaters - “semi-vegetarians” (5).
In the 1970s in the UK, about 11000 people were recruited from health shops or other avenues such as health food societies to participate in a long term observational study . 11000 health conscious, health seeking individuals. Less than half were vegetarians/vegans and they were studied for until death, or for up to 17 years if they survived the length of the study. There were initial questionnaires and follow up interviews and questionnaires.
When the results were analysed there was no difference in mortality rates between those who ate meat and those who didn’t. The group as a whole had much lower mortality rates compared to the general population and this was linked to a lower amount of smokers in the group studied. The most significant observation from this study was that daily fresh fruit consumption correlated well to a reduced risk of mortality from disease (6). (Again, correlation not causation, but another little point to keep up your sleeve for the next fruit-fearing, fructose warrior who gets up in your grill for eating an apple).
Between 2006-2008 in NSW, Australia, nearly one quarter of a million people, aged 45 and up, took part in a dietary survey and six year follow up. This observational study also looked at dietary choices and mortality rates and found no differences between regular meat eaters and non-meat eaters. Researchers concluded that they found no correlations between vegetarian, pescatarian or semi-vegetarian and improved mortality rate. However, when compared to the general population, they did state that those who completed the survey were less likely to be smokers, more physically active and less likely to be overweight and obese (5).
These are just two observational studies, but there are many others which also conclude that when lifestyle factors (smoking, alcohol, exercise, fruit and vegetable intake) are accounted for, there does not appear to be a clear correlation between excluding meat from the diet and mortality from disease (7)(8)(9).
One more point which is important to define when talking about observational research and nutrition is relative risk versus absolute risk. These terms are not usually defined when trying to make a particular food sound scary -
”Each 50g portion of processed meat eaten daily increases the risk of colorectal cancer by 18%” (10). This is relative risk, a comparative risk. Your chance of colorectal cancer is estimated to rise by 18% compared to the same person who doesn’t eat that 50 grams of processed meat each day.
Absolute risk is your chances of getting a disease over a period of time - this is the one which should be reported because it is more fair and less sexy - exactly the reasons it doesn’t get included in articles and “mock-umentaries”.
Looking specifically at colorectal cancer. Your absolute risk of getting colorectal cancer as a human at age 50 is 1.8% (11).
Taking the above relative risk increase, if you eat 50 grams of processed meat each day you increase your relative risk by 18%. To apply this to your absolute risk you multiply your absolute risk by 1.18.
0.018 x 1.18 = 0.021
So by eating 50 grams of processed meat each day of your life, you’ve taken your absolute risk of developing colorectal cancer from 1.8% to 2.1%. Not sexy, not headline grabbing, not worth using on Netflix or a clean eating blog.
If you want a summary of the research around nutrition, taking into account the strengths and weaknesses of studies and claims, in all honesty the Australian Dietary Guidelines is a great place to start. It is inclusive of all foods and rates the claims for and against particular foods against a scale of research strength. Before reading blogs about restricting any particular foods or before watching any more Netflix-Nutrition, take some time to read the Australian Dietary Guidelines to give you some context around what you may hear.
Furthermore, if you’d like more education on nutrition and how to find a way of eating that suits you and helps you life a healthy, enjoyable life; contact us today.