Carrots help you see in the dark and other nutritional myths
From antiquity carrots have been said to be good for the eyes. It turns out that this ‘old wives’ tale is entirely true and NOT one of the nutritional myths!
Carrots are a good source of beta carotene which is converted into retinol in the body, essential for visual pigment formation. So some nutrition myths’ are actually age old wisdom based on generations of observation.
But nutrition and its relation to health is beset with misinformation and changing attitudes and perceptions. For example, for around 40 years we have heard that dietary fat causes obesity, heart disease and should be avoided. Recently though it has become clear that since the early 1980s people have been eating less fat but getting more overweight all the time!
It may be sugar rather than fat that has driven the epidemic. The jury is out on this question at the moment, but the story that serves to illustrate the ‘truth’ about nutrition can be a hard to pin down. Here are some other examples of ‘nutritional myths’.
My metabolism is slow, that’s why I’m overweight
A slow metabolism is actually a rare cause of obesity (such as in hypothyroidism). Actually the more we put on weight, the more our metabolic rate increases, meaning we need to eat more than before to maintain or increase weight.
There’s no difference between organic and non-organic foods
The latest evidence clearly suggests that although the differences aren’t huge, organic foods do have greater micronutrient content and are certainly bringing less herbicide, fungicide and pesticide residue to the table!
You need a personal trainer to learn ‘fat burning exercises’
All you need to do to burn fat is put up your feet and watch TV! The body prefers to burn fat as a fuel, so unless you’ve recently eaten or are engaged in exercise, you will naturally preferentially be using fat as a fuel.
Read more about fats in our macronutrients chapter.
Actually the so called ‘resistance’ exercises (weights) will long term lead to more ‘fat burning’ overall compared to low intensity workouts as an increased muscle mass raises the use of fat as a fuel at all times — even when sleeping.
Water is the best hydration drink
Water is vital and most of us need to drink more of it. But it is better retained in the body (more hydrating), if it is taken with a little juice. This gives it time to get to cells where it’s needed before we pass it out as urine.
Red meat can’t be digested properly and builds up in the gut
Very rarely true. The body is incredibly efficient at absorbing the protein and fat in meat and it doesn’t get wasted. A general blockage of the gut can occur due to constipation, but this isn’t a result of eating meat.
A high fibre diet is good for everyone
While it’s true some people get real benefit from high fibre diets, the roughage in grain based foods can actually irritate the lining of the gut for others and so it’s important for each individual to listen to their body and know what’s right for them personally. Gentler forms of fibre in fruit and most vegetables tend to be less problematic.
We can get all the Vitamin D we need from sunshine
This is true if you live in a sunny country and spend time each day outdoors with your shirt off. The rest of us need to top up with food sources such as eggs and oily fish, or even supplements, especially during the months of October to March.
Vegetarian diets are the healthiest
It’s true that many studies show vegetarians are healthier than meat eaters. But if you study people who only eat modest amounts of the best quality and cuts of meat then this difference gets smaller. If we factor in the reality that most vegetarians tend to be non smokers or drink large amounts of alcohol, exercise more, be better educated and in a higher socioeconomic class, then the differences in health status become much smaller. Also, strict vegetarians may run the risk of Vitamins D and B12 insufficiency and could even lack important fats such as those found in fish.
An apple a day keeps the doctor away
Well this myth, unlike many other nutritional myths, is half true. Apples are great, but the latest evidence suggests that not just 5 fruit and vegetable portions a day, but up to 10 can produce the maximum benefits to your health. Variety seems to be the key also, so eating a range (rainbow) of different fruit and vegetables is better than lots of just one sort.
Eggs are bad for your heart
Eggs contain cholesterol and a high cholesterol level in the blood increases risk for cardiovascular disease. This is why eggs are sometimes believed to be risky for heart health. In fact most of the cholesterol in our bloodstream is made endogenously (within the body) by the liver. Eating a diet high in saturated fats, not foods containing cholesterol, that stimulates overproduction and is mostly responsible for hypercholesterolemia (high blood cholesterol).
Fish is ‘brain food’
It turns out that this ‘nutrition myth’ is true! Fish, especially oily fish, is high in docosahexaenoic acid (DHA) which is vital for brain formation and function. This form of fat is essential for the development of the nervous and visual systems. Some studies have even shown that fish oil supplementation of children can raise their IQ!
Wholegrain cereals are good for you
This is both true and false. Within a typical modern diet wholegrain foods, such as wholegrain bread, are probably healthier than more refined versions. Interestingly, however, looking at the history of human beings through the fossil record we can see that when humans moved away from a hunter-gatherer lifestyle they lived less on average. Farming and eating a grain based diet meant that they grew less tall and had worse teeth. It’s because of these findings that people became interested in the ‘pre-agriculture’ or Paleolithic diet.