SCOTLAND has recently been reported to have higher obesity rates than many other countries — including England. The differences between neighbouring countries are very small, but they have been persistent over the years.

“Obesity”, the modern disease-process, of excess or abnormal body fat accumulation, is a natural, normal survival strategy. It allowed our ancestors to survive long winters. So most people have that ability to store extra food calories for future use.

That wasn’t the only survival strategy — other people couldn’t put on weight, but could run fast and far to find food.

We see both these types of human physiology today, but prolonged food shortage is rare. It used to be, and still is the case in low-income and war-torn countries, that people living in poverty struggle with undernutrition and thinness. But they quickly swing into overnutrition, obesity and type 2 diabetes if affordable food is readily available.

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November 14, as I write, is World Diabetes Day.

There are now 830 million people with type 2 diabetes, worldwide, and another billion or more people on the slippery slope with prediabetes. More than 700 million people with diabetes are quite young and live in the world’s poorest countries, where medical care is sketchy or non-existent.

The reason is weight gain, which includes a very common genetic predisposition, plus the effect of moving from traditional foods to cleverly marketed imported manufactured foods in shiny paper.

People in poverty and social deprivation understandably seek ways to improve their sense of status and feel better about themselves. That can entail using very limited money to buy symbols of perceived affluence, such as branded clothes and other Western items, hence the flourishing trade in fakes in lower-income counties.

Food marketing and product placement can also present a desirable status above traditional foods, which become portrayed as foods of poverty. Foods that are heavily marketed are usually cheap and convenient, but have a large profit margin for wealthy food industry investors.

However, they are manufactured, ultra-processed from ingredients that are themselves mostly inedible, and high in flavour, sugar, fat and thus calories, which are stored as body fat. Complications like type 2 diabetes and high blood pressure are quick to emerge.

This pathway of chronic disease development is clear in low-income countries, but we see reflections of the pattern behind the obesity epidemic in most countries, including Scotland, where on average everyone consumes about 300 calories a day more than 50 years ago.

So adults are on average a stone or more heavier. Sadly, people from more socially deprived communities are more likely to rely on “added-value” manufactured food, and to gain weight, and there is a knock-on for weight gain in their children.

There are many factors which might contribute to the slightly higher obesity rates in Scotland. Our climate and roads are less conducive to safe walking or cycling – children who walk to school are less likely to gain excess weight.

More Scots may sensibly have stopped smoking recently and gained a pound or two – the health benefit from not smoking greatly outweighs the effect of minor weight gain.

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The overall levels of social deprivation are similar in England and Scotland, but these figures can be misleading because, for example, car ownership is considered an exclusion.

Cars are essential in most Scottish rural areas, so rural social deprivation may not be included.

Lack of a car used to make supermarket shopping harder, so people relied more on small shops with little fresh food, but online shopping and delivery after Covid may change that. Perhaps we are just more generous with our food. Heavy binge drinking does promote weight gain, and is slightly more frequent in Scotland than other countries.

What are we to do about obesity, to help people towards healthier happier lives?

Reducing social deprivation could have big effects, and better education does help to avoid unwanted weight gain, but not completely. We still don’t teach young children (or medical students, or politicians and journalists) much about basic nutrition.

However, the main driver of the obesity epidemic in Scotland like everywhere else is the huge change in eating habits over the last 50-100 years.

We are running a successful project out of Glasgow University for weight loss and remissions of type 2 diabetes using only traditional foods in Nepal, where type 2 diabetes is now common and largely untreated.

So, what about Scotland? Our research dietitians put together a version of a traditional Scottish diet. It is based on what many people ate 100 or more years ago, when obesity was rare, and calculated to provide the vitamins and minerals needed for health.

It involves porridge for breakfast, and then lentil and vegetable soup and a bread roll for lunch, plus a piece of fruit with each meal.

For people who want to lose a stone or two, the evening meal for a few weeks is another bowl of lentil and vegetable soup (many different recipes!).

If the aim is just to avoid gaining weight, the portion sizes can increase a little, and the evening meal can be varied, to fit in with the family etc.

Vitally though, no manufactured foods or snacks between meals.

That Scottish traditional diet approach was called the “Nae Doubts Diet”, but we posted it on the University of Glasgow website as the “No Doubts Diet”.

It isn’t the only effective diet, but it is guaranteed to work if people follow it properly. Many people have – it costs nothing, and it can be fun.

Mike Lean is professor of human nutrition at the University of Glasgow, and consultant physician at Glasgow Royal Infirmary