Five servings of fruit and
vegetables per day is the UK nutrition guide. But why are fruits and vegetables grouped together in this statement? They bear little relationship to each other in how they impact your health. While fruits are often brightly colored to attract predators and are sweet to encourage you to eat them, vegetables more often come with toxins to dissuade you from eating them and as a result, often require special preparation.
When I am speaking to a group about nutrition and how to heal your body with food, a question is sometimes asked about fruit. Surely it is good, and are we not being told to eat it daily? It contains natural fruit sugars, so cannot be harmful. There is a lot to unpack here so let’s work through the history and science.
Historically humans, birds and many animals have always eaten fruit. It is clearly an ancestral food. However, there are some significant differences between the fruit we see in the supermarket and the fruit our ancestors ate. First the ancestral fruit was not stored in a cool, managed environment and was not available all year around. It was out there growing on the bush or tree and was attractive to all manner of insects, birds, and animals. It had a relatively short ripe season before it was eaten or fell off the tree. There was no farmer protecting it from fungus and insects or putting up bird netting to ensure that it stayed in good condition.
Selective breeding of fruit varieties has changed the ancestral fruits from small, less-sweet varieties to large, sweeter varieties and increased the yields significantly. The original kiwi fruit for example was a small brown plumb like fruit (called a Chinese Gooseberry), before being extensively bred. Most important though is the availability. Our ancestors only had fruit that was in season where they lived and only had the fruit that was not taken by animals, birds, and insects. Once picked it had to be eaten almost immediately.
The breeding of fruit varieties has also changed the fruit in other ways. Fruit has been bred for longer shelf life and to make it able to withstand the rough handling of sorting and packing machines without damage. This changes the fruit in ways that we may not always understand. As a similar example, the breeding of wheat to increase yields in recent years has increased the level of gluten. In another example I am told that heritage tomato varieties have much better taste but their skins damage very easily with handling, so are unsuitable for the supermarket.
Fruit sugar is called fructose. In recent years it has been discovered that the human body metabolizes fructose in a completely different way to other sugars, so different, that it does not spike insulin in the same way as glucose. Dietary fructose is immediately transported to the liver after eating. In the liver it is converted to glucose for energy or uses a process called lipogenesis to convert it to fat for storage within the liver or in our fat cells. Fructose does not stimulate insulin in the same way as glucose because of this different metabolism. This means that a food manufacturer can load a processed food with fructose and “claim” it to be a low GI food and therefore healthier. Unfortunately, excess fructose going to the liver can eventually result in fatty liver disease (NAFLD). Late stages of this will damage a liver forever.
At an ancestral level this different fructose metabolism might have had advantages for primitive people, encouraging them to eat lots of fruit when it was available, because the time window was so small, and they may not get anymore for a long time. Stored in the liver, the resulting fat would be available for many days.
It is fascinating that fruit generally comes ripe just before winter, when many animals need to build up fat reserves to last them through this cooler period. In addition, the fructose (fruit sugar) in fruit is uniquely managed in the body, going directly to the liver to be turned into fat and stored.
Much of the fructose in today’s diets comes from High Fructose Corn Syrup, (HFCS), which uses a process invented in Japan to convert corn into this sweet syrup. This factory-made product has become a very common food additive because it is very sweet, is low cost and being a liquid is easy to handle in the factory. Another item used regularly by manufacturers to make food sweet and “adjust” your view of the nutrition label is fruit juice concentrate which is another name for concentrated fruit sugar.
The thinking that fruit is healthy has driven the establishment of the fruit juice industry where fruit is pulped, filtered to remove unwanted fiber, and packed for easy handling. Unfortunately, this concentrates the sugars while removing most of the fiber. In some cases, sugar is also added to heighten the sweetness. In a normal piece of fruit, the fiber and bulk of the fruit, helps slow down digestion and increases the level of nutrients available to your body. My advice is to avoid fruit juice because the concentration increases the level of sugars markedly and overcomes your natural satiation mechanism. It is easy to drink 6 apples as fruit juice but pretty much impossible to eat 6 apples at one time.
Fruits also develop higher levels of sugar as they ripen, so a green banana will be better for your blood sugar balance than a ripe banana. As an aside, green banana flour has a massively high level of resistant starch which acts as fiber in your body.
There is a wide range of sugar levels in fruits and a little knowledge here can make choosing the better fruits easier. If it is a berry, such as blueberries, raspberries, or strawberries then it is generally much much lower in sugars than other fruits such as apples or bananas. Strawberries are perhaps the best with only 4.9 grams of sugar per 100 grams of fruit. Compare this with banana at 12 grams per 100 grams of fruit. This means that an average sized banana converts to the equivalent of 6 teaspoons of sugar. As already said, greener fruit has lower sugar levels.
Fruits from the nightshade family, including tomatoes, eggplant, capsicum or peppers come with their own toxin. Solanine, which can cause muscle stiffness, arthritis, dizziness, sore throat, stomach cramps, vomiting and headache, if you are susceptible to this. Cooking well, will reduce this but will never completely eradicate the problem. Early people tested food on pigs and feeding them nightshades apparently gave pigs arthritis so were mostly avoided until the last 100 years or so. They taste good. Maybe they should be eaten sparingly.
To get best value from eating fruit, I would suggest you attempt to mimic the way fruit was eaten by our ancestors. Only eat fruit that is in season in your location and limit yourself to one piece per day making sure you eat the whole fruit including the skin, where appropriate, to get all the available nutrients. If eating “trucked-in” fruit, I would suggest limiting yourself to only one piece periodically.
If choosing sugars, I believe that glucose is better than fructose for your body.
For more information on using your food for medicine, go to my website at www.takebackyrhealth.com or use the link there to jump to my book on Amazon.
Good Luck. George Elder