Carbohydrates are considered by many to be “the enemy” of healthy body weight. The ‘no carbs before Marbs’ mantra (from the TV show The Only Way Is Essex, about holidays in Marbella) reflects a widely held view that carbs lead to fat gain.
This is based on the fact that carbohydrates – such as bread, potatoes, pasta, cakes and cookies – are broken down in the body into glucose – which can raise blood sugar levels; Over time, this can lead to weight gain and health problems, such as type 2 diabetes and heart disease.
But has our understanding of this been wrong?
A study, published in the journal Cell Metabolism, suggests that in some people it is actually fats and proteins, rather than carbohydrates, that cause high blood sugar levels. Levels are generally kept in check by insulin, a hormone produced by the beta cells of the pancreas that helps cells absorb glucose and use it for energy.
Insulin also helps the body store extra glucose as glycogen, primarily in the muscles and liver (then returned to the blood when blood sugar levels are too low).
Testing blood sugar levels at home with a glucometer is usually done by people with diabetes or at risk for it.
But if the cells stop responding to insulin, excess glucose circulates through the bloodstream.
The pancreas then pumps out more and more insulin to keep blood sugar low, until it can no longer keep up, causing type 2 diabetes. Over time, high blood sugar levels damage blood vessels. blood and nerves.
In the latest study, scientists at the University of British Columbia in Canada took 140 pancreatic islets (clumps of pancreatic cells that include beta cells) from deceased human donors with and without type 2 diabetes.
They also took pancreatic islets made from stem cells (“master” cells that can form different types of cells in the body). The experts then looked at how much insulin they secreted in response to carbohydrates, proteins and fats.
The study demonstrated, for the first time, that some human pancreatic islets produced more insulin in response to fatty acids (fats) and amino acids (proteins) compared to glucose (carbohydrates). This turned traditional thinking upside down.
So could this change the advice some people are given?
“It’s an interesting concept and may offer some explanation for the variability we see in terms of how people respond to specific diets (for example, low-carbohydrate diets), so we know that there is no single measure that works for everyone,” says Dr Efthimia Karra, a consultant endocrinologist at the Royal Free Hospital and Princess Grace Hospital, both in London.
Aisling Pigott, diabetes dietitian at NHS Wales, said: “In the clinic we see (from glucose monitors) that some people experience an increase in glucose from carbohydrates and others may respond more to protein and fat. It depends on the individual and how much they have eaten.’
No carbs before Marbs was the mantra of some of the stars of TV show The Only Way Is Essex.
The results of the study, he says, are confirmation that no two people are alike in terms of how they respond to food and that metabolism is complex.
“It could help eliminate the guilt and frustration that some people with diabetes feel when they work hard but can’t lose weight or improve their blood sugar levels,” he adds.
A high-fat diet may not necessarily be the answer, as it can cause fat to accumulate around the abdomen. This type of fat increases inflammation in the body, which is thought to make cells less responsive to insulin.
This latest research has implications for countries like the UK, where our diet tends to be high in carbohydrates, adds Roy Taylor, professor of medicine and metabolism at Newcastle University, who helped develop a low-calorie diet that has been shown which reduces type 2 diabetes. diabetes in remission.
It involves taking meal replacement soups and shakes for the first 12 weeks (for a total of between 800 and 900 calories each day).
Professor Taylor says there is a place for carbohydrates in our diet, but the problem is the added calories they contain. “It’s very easy to eat too much mashed potatoes or consume too much pasta or rice,” he adds.
Additionally, consuming too many carbohydrates can trigger different responses in the body, depending on how sensitive it is to insulin, explains Professor Taylor. “If you have normal insulin sensitivity, breakfast cornflakes target muscle glycogen stores, but if you don’t, the body immediately transfers much of that glucose to fat.”
Everyone has a different sensitivity to insulin, dictated by genes.
It may not be obvious if you are insulin resistant, so it is worth checking your family history. If a family member has suffered a heart attack or diabetes, consider reducing carbohydrate consumption, says Professor Taylor.
This is because if you are insulin resistant and excess carbohydrates are stored as fat, it can lead to clogged arteries, increasing your risk of having a heart attack or stroke.
Professor Roy Taylor says it may not be obvious that you are insulin resistant
But this can be modified to a small extent through regular exercise and weight gain or loss.
Other factors, such as aging and hormonal changes, can affect our response to food, adds Aisling Pigott, who is also a spokesperson for the British Dietetic Association.
“For example, when women are perimenopausal and menopausal, their estrogen level drops, which affects their muscle maintenance so they may have a higher percentage of body fat than before, and we know that this increases insulin resistance.”
Similarly, the stress hormone cortisol can prevent insulin from working as well as it should.
When it comes to the latest research, experts agree that more studies are needed to determine if this translates to people. As Professor Taylor says: “It is important to note that some of the study results were related to the time the islets were in culture in the laboratory (the longer they were in the laboratory, the more time they had to secrete insulin). i.e. higher amounts), this is very far from the situation in real, living people.
“Type 2 diabetes is a tremendously simple disease: people who approach diabetes often become too heavy for their own bodies,” he adds.
“Keep in mind that any weight gain in adult life is due exclusively to fat: we do not naturally develop additional muscle, bone or brain tissue, so people’s weight in middle age should really be what they were. when they were 20 years old.”
His views coincide with those of Dr Karra: “Ultimately, the key message remains to maintain weight within healthy levels and it may take an element of trial and error to find the best diet to achieve this for you.”
And in the short term, there is a simple but key tip. As Aisling Pigott explains: ‘It is essential to be active within an hour after consuming a meal.
“This can greatly reduce the rise in glucose levels after meals because when we move, our cells absorb glucose for energy and increases the impact of the insulin we have, which in turn reduces the resistance of our cells to she”.
She adds: “This doesn’t have to mean going to the gym – a gentle walk or simply tidying up the kitchen can help – but it really helps to avoid sitting still during this time.”
