My life in nutritional science
Weight control problems
Are you finding it more difficult to control your weight these days? Most people are. Which explains why 25% of the population has a BMI (body mass index) classified as obese, almost half are overweight and 2 million people are currently diagnosed with diabetes, with an estimated 2 million more who also have diabetes, but have not yet been diagnosed.
Even more worrying, childhood obesity is at an alarming level and rising – with the Royal College of Physicians predicting that as many as 50% of British children will be obese by 2020.
All despite the fact that we, on average, eat less than we did 60 years ago! How can that be? And is there an answer?
There is an answer and it offers sustainable weight loss. But first let’s list the five main reasons for our increasingly tough battle of the bulge. Then I’ll offer the solution.
The wrong food …
We evolved bodies that normally ran on lots of fruits, nuts and vegetables (gathered), plus occasional lean meat and fish (hunted) ie low calorie, high nutrition, high fibre foods.
Today the situation is totally reversed.
The foods that surround us are too often high calorie, low nutrition, low fibre.
In particular we have moved away from fresh foods to processed foods that incorporate far too much fat, salt and sugar – and other refined carbohydrates: foods like bread, biscuits and cakes baked with refined flour and sugar.
These – together with foods like pasta, potatoes, and many breakfast cereals – cause the blood sugar level in our bodies to rise sharply after eating. Each ‘sugar rush’ triggers a surge in insulin, released from the pancreas, which clears glucose from the blood.
A small amount of this glucose is driven into the liver, and some is absorbed by the muscles for energy requirements. However, since we normally engage in little activity, this leaves a lot of surplus glucose – which then goes straight into our fat stores, as well as causing damage to our arteries and other tissues.
The effect of food on blood sugar levels is known as the GI (Glycaemic Index) effect. A high-GI food like pure glucose (GI of 100), causes the fastest rise in blood sugar. Low GI foods (GI under 55) trigger a slower and lower rise in blood sugar.
But high-GI foods cause more than a direct deposit of glucose into fat stores – they also satisfy you for a shorter time than low GI foods – soon leaving you hungry and prone to snacking and over-eating.
Over time an excess of high-GI foods, combined with a low exercise lifestyle, can cause people to be resistant to insulin and eventually diabetic. It is the switch to high-GI foods that is a root cause of the epidemic of adult and childhood weight problems.
There’s another problem. Over the last fifty years the amount of fibre in our diet has dropped dramatically. Fibre is the slimmer’s friend because it has half the calories of protein or carbohydrate – some forms of fibre have no calories at all – and it makes you feel full and satisfied.
The result of these changes in food quality is that many people suffer from what has been termed ‘Type B’ malnutrition.
Type A malnutrition is represented by the emaciated figures from a famine. People with Type B malnutrition are overweight from an excess of calories, yet simultaneously suffer from nutritional depletion, which in turn can increase the risk of developing degenerative illnesses like diabetes, heart disease and cancer.
… consumed in the wrong amounts
Many restaurants today serve excessively large portions and add fats and cream to many dishes – because they taste good and they are cheap ingredients. And portion sizes of many popular snack foods (eg. muffins in coffee bars) have doubled in the last 20 years!
Calories are directly proportionate to portion weight. The heavier the item, the more calories. Sounds obvious, but many food packs quote calories per 100 grams – which may look reasonable. However, if the portion size is 400 grams you may well be getting a lot more calories than you imagined!
… often in stressful conditions
Modern lifestyles result in more stress – in fact a recent Gallup poll found that 80% of workers feel stress on the job and 40% of workers report their job is “very or extremely stressful”.
When we are stressed, the body produces not just adrenaline, but cortisol. Not only does cortisol raise cholesterol and blood pressure, but it also stimulates the release of insulin and the maintenance of high blood sugar levels.
The result is an increase in physical appetite and weight gain. (The result is also often an increase in ‘psychological’ appetite and the desire for comfort eating or ‘mood food’.)
And cortisol can also affect where you put on weight.
Doctors have shown that stress and elevated cortisol levels tend to cause fat to be deposited in the abdominal area rather than on the hips. This type of fat is often known as “toxic fat”, since fat in the abdominal area is strongly correlated with the development of cardiovascular disease including heart attacks and strokes.
… by an ageing population
Many women find that they gain weight during the menopause. Some researchers believe that this happens because, as oestrogen levels decline around this time, fat cells take over some of the production of oestrogen and increase in size and number.
In men, testosterone helps the body maintain lean muscle and burn fat. But a decline of testosterone with age can cause a loss of muscle and an increase in fat.
Moreover, in both sexes, human growth hormone levels decline with age. This also results in more fat and less muscle mass. Muscle, and what is known as lean body mass, burns more calories than fat. So the more muscle or lean body mass you have, the higher your metabolism and the easier it is to lose weight.
Yo-yo dieting has the opposite effect. Each time you lose weight and then put it back on again, you increase the proportion of fat to lean mass – and make it even harder to lose weight next time. That’s why learning how to keep the weight off permanently is so important.
… whose activity level has dropped by almost half
Before the invention of our cherished labour-saving devices – cars, lifts, motor mowers, vacuum cleaners, dishwashers and washing machines, we used about 1,000 calories a day more in physical activity than we do today.
And before we had central heating we burned at least another 500 calories a day to maintain our body temperature.
Consequently we now expend about half the energy of our recent ancestors and that makes weight control all the more difficult – and it reduces our health-span.
These five reasons are why we battle with weight as never before.