With our busy lifestyles, many of us do not dedicate enough time to ensuring we have a healthy diet. But we are what we eat, so let’s talk about nutrition.
Many people eat too much processed food, too many takeaways, too much sugar and drink too much alcohol. As a result, many of us are overweight or obese, and poor nutrition leads to numerous diseases and reduces life expectancy.
Key facts from the World Health Organisation
Worldwide obesity has more than doubled since 1980.
In 2014, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 600 million were obese.
39% of adults aged 18 years and over were overweight in 2014, and 13% were obese.
Most of the world’s population live in countries where overweight and obesity kills more people than underweight.
42 million children under the age of 5 were overweight or obese in 2013.
Obesity is preventable.
The NHS has provided an Eat Well guide. It says we should:
Eat at least five portions of a variety of fruit and vegetables a day
Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates. Choose wholegrain where possible
Have some dairy or dairy alternatives (such as soya drinks and yoghurts). Choose lower-fat and lower-sugar options
Eat some beans, pulses, fish, eggs, meat and other protein. Aim for at least two portions of fish every week – one of which should be oily, such as salmon or mackerel
Choose unsaturated oils and spreads and eat in small amounts
Eat foods high in fat, salt and sugar less often and in small amounts
Drink plenty of fluids – the government recommends 6-8 cups/glasses a day
What foods do we need to avoid?
Studies have shown that high-fat, high-calorie foods are addictive and affect the brain in much the same way as cocaine and heroin. Processed foods and drinks have been developed so they are tasty, can be mass produced and have a long shelf life. If we could visit the factories that make these foods and drinks, we would probably never consume them again. We crave foods that are high in sugar, salt and fat, and so processed foods are usually high in these three very unhealthy and artificial ingredients. By processing foods in a certain way they can be very rewarding to the brain. Comfort eating processed foods increases dopamine and makes us feel better.
Processed foods are likely to contain numerous chemicals including colourings, flavourings and preservatives. If you read the ingredients for processed foods you will see a list of chemicals – would you consider them food?
When processed and junk food is consumed too often, the excess fat, carbohydrates, and processed sugar contributes to an increased risk of obesity, cardiovascular disease, diabetes, and many other chronic health conditions.
What affects our nutrition?
Several hormones play a role in nutrition. When we are hungry, the hormone ghrelin (lenomorelin) is produced in the stomach and tells us to eat. Cholecystokinin gives us a feeling of fullness. Leptin is the most powerful appetite-suppressing hormone and tells us when to stop eating. Insulin regulates sugar in our blood and also tells the brain to stop eating. Certain foods, such as meat, poultry and diary, increase the release of dopamine, which can make us feel happy and more alert. Serotonin is released after eating carbohydrates, and it enhances calmness, improves mood and reduces depression.
Our gut microbiome is key. Gut bacteria are responsible for extracting some of the nutrients from our food and produce a range of enzymes, chemicals, hormones and vitamins. Scientific data suggests that the more diverse our gut bacteria, the better it is for our health and wellbeing. Our diet, lifestyle, our fitness, the use of medications/antibiotics and our environment all affect our microbiome. If we get stressed, do not exercise, eat badly, or take too many antibiotics we can adversely affect our microbiome.
One easy way to help keep a diverse population of gut bacteria is to eat a diverse diet. Our diet should be full of a variety of fresh whole fruit and vegetables and foods high in antioxidants, and there is some suggestion that eating fermented foods such as sauerkraut may help. Prebiotics are found in many unprocessed vegetables and fruits including lentils, asparagus and Jerusalem artichokes, and probiotics are found in yogurt, kombucha, kvass, kefir, fermented food and cultured vegetables. We need to stick to dietary guidelines for our intake of processed sugar and grains, pasteurised dairy products, foods high in bad cholesterol, trans and hydrogenated fats and we should not juice fruit but eat it whole. As we age, we often reduce the variety of our food and this reduces the diversity of our gut bacteria.
There are many studies looking at genes that predispose people to being obese. The main gene is called FTO – fat mass and obesity-associated gene. This gene changes the way our brain thinks about food – it works by letting the brain think we are thinner than we are, causes craving for sugar rich foods and makes us think we are eating less than we actually are. It is related to how the reward pathways work in the brain. People have a different versions of the gene. Those with two at-risk copies of the FTO gene – called a double variant – are 70% more likely to be obese but the good news is that they are also more likely to lose weight through exercise. Those with one at-risk copy are also more likely to be obese.
Fad diets and surgery – not the answer…
Due to our addiction to unhealthy diets, in particular those combining sugar and fat, the diet industry is worth billions. We are bombarded with information about new fashion diets, from the cabbage soup diet to diets where you just drink shakes for months on end. All fad diets are unhealthy and unsustainable. What we need to do is address our relationship with food and eat healthily, filling ourselves up with healthy food.
Some people will go to the extreme of having surgery such as gastric bypass operations. Obesity surgery in the UK costs the National Health Service £85 million per year. The only surgery proven to be effective for weight loss is bariatric surgery, which reduces the stomach size from 900 mm to 30 mm. This is normally done by inserting a gastric band or performing a gastric bypass. But it has risks and is expensive.
Dr Steve Bloom and Tricia Tan from Imperial College, London are looking at a miracle injection which could have a similar effect to a gastric band. They are looking at a triple gut hormone infusion which reduces appetite and food intake. At the moment the trial is pumping a steady stream of hormones into the gut and participants are eating 30% less than the controls. The infusion only lasts for one meal but they are hoping to develop an injection that will have a longer effect.
There is also a lot of work being done into gut bacteria. There have been studies looking at twins where one is a normal weight and one is obese. Scientists have transferred the poo from the twins into mice. Those mice infused with the poo from the fat twin, became fat but there was no such effect with the poo from the thin twin. The theory is the gut bacteria in the poo are having an effect on the mice; these bacteria may influence the hormone levels in the gut. In the USA this study is being tested on humans. Poo from lean donors, which is thought to contain ‘good’ gut bacteria, are being transplanted into the gut of obese people. One hunger hormone, Glucagon-like peptide-1 (GLP-1)- rises after the transplants. Other scientists are trying to isolate the individual bacteria.
Professor Tim Spector from St Thomas’s Hospital, London and author of The Diet Myth; the real science behind what we eat, is looking at twins and investigating gut bacteria. He has found that high levels of one particular gut bacteria, the person will rarely get fat. He is looking at ways we can increase levels of this gut bacteria. He suggests we eat a high fibre diet with a lot of fresh fruit and vegetables.
So it looks like a combination of our genes, hormones and gut bacteria can effect our weight. But we must not use these as excuses. We should try and make the time to plan meals, eat healthily and take control of our nutrition. It is good for our health!
Read More:
https://www.bbc.co.uk/iplayer/episode/b07fys2y/horizon-20152016-11-why-are-we-getting-so-fat
Image credit: www.mirror.co.uk
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