NHS soups and shakes diet: Doctor and nutritional scientist Professor Robert Thomas gives his verdict on diabetes diet

A major study published in the The Lancet Diabetes & Endocrinology journal confirmed that early diabetes and pre-diabetes especially in obese people can be reversed with dietary manipulation. At first sight, the results were impressive.

Of the 945 who completed a full year of the programme, the average weight loss was a significant 16kg. Blood tests also revealed 32% had gone into diabetic remission – meaning they had normal blood sugar levels for at least three months. Any strategy to reduce the skyrocketing incidence of diabetes is certainly most welcome. The number of people diagnosed with diabetes in the UK has quadrupled from 1 to 4 million over the last 10 years and is estimated to rise to 5.3 million by 2025.

Type 2 diabetes in particular has been growing at the particularly high rate and is now one of the world’s most common long term health concern. Diabetes is associated with premature aging, peripheral neuropathy, eye problems and death from heart disease, stroke, cancer and many other degenerative illnesses. 

The trouble is with the strategy of just eating soups and shakes is that it is not very appealing so unlikely to be maintained in the long term, especially outside the protection of a clinical trial. Even with intense supervision in the study, of many thousands invited, hundreds completed the year-long programme. Only 12% of those who embarked on the brutal diet managed to stick to it for a full year. 

In my view, it would be better to aim for regular incremental changes in lifestyle that lead to long term, sustained changes in behaviour. There is lots of evidence that diet, exercise, and weight management can slash the risks of diabetes. Here are the strategies with the most evidence.

Avoid sugary foods and drinks which are high in calories but are not satiating (make us feel full). We, therefore, carry on consuming them even when our body has had enough calories leading to excess weight gain. Processed carbohydrates and sugars also have a high glycaemic index (GI), causing blood glucose levels to increase rapidly. This stimulates insulin release by the pancreas, which promotes the storage of glycogen in the liver and eventually fat in the tissues tissue. The initial high sugar levels tricks the body into thinking it has eaten a very large meal, so it overproduces insulin, which then causes sugar levels to drop, quite dramatically, which in turn stimulates hunger and fatigue. Over time these high peaks in insulin leads to insulin resistance and diabetes.

Increase exercise and avoid sedentary behaviour. The vast majority of people in the UK are too sedentary, so, many of the calories they consume end up being stored in the body as fat. A good target is two and a half hours of moderate to intensity exercise, such as running, cycling or fast walking, every week. Ideally, try to exercise first thing in the morning, before breakfast, even if only for 20 minutes. This means the stomach is empty, so the body has to use energy from stores in the liver and fat tissues. It also extends the period of overnight fasting which has been linked to a lower diabetes risk.

Eat more whole foods and fibre and less processed high-calorie foods. Ultra processing foods, often high in fat and sugar, have the bulk and fibre removed reducing the need for chewing, and allowing them to be consumed and absorbed more quickly. Whole foods such as wild rice and whole meal bread, on the other hand, have to be chewed as they have more bulk and fibre, making them slower to eat and more satiating, without increasing the calorie content. 

Enhance your gut flora. Unhealthy bacteria in the gut contributes to a state of chronic inflammation, leading to low mood and fatigue, which demotivates individuals from exercising and eating better. Strategies to enhance gut health such as increasing dietary intake of fermented foods including live unsweetened yoghurt, miso, kimchi, kefir or sauerkraut, and in some cases, taking a good probiotic supplement, would be a sensible option. 

Avoid snacking between meals. Hunger has become an unacceptable sensation in western societies, but it should be embraced, because this is when weight starts falling off and insulin levels drop. The fall in blood sugar that occurs when we’re hungry triggers the breakdown of glycogen in the liver and the conversion of triglyceride fats into fatty acids and glycerol to be used for energy. Instead of grazing throughout the day, it is best to have a meal and allow it to digest completely before the next one. If you do feel hunger pangs, try drinking water, going for a brief walk or occupying yourself with an activity to help take your mind off food. 

Eat more phytochemical rich spices, herbs and blueberries. A combined analysis of two major population studies found that people with a higher intake of phytochemicals had a lower incidence of T2DM. Phytochemicals rich foods are often high in pulp and fibre which help gut mobility and act as prebiotics reducing dysbiosis. Phytochemical rich foods also slow the glycaemic index of carbohydrates, improving insulin sensitivity. It is widely recognised that receptors in the stomach interact with capsaicin, a phytochemical responsible for the ‘heat’ in chillies, which helps with reducing calorie intake by signalling a feeling of fullness. Green tea, rich in catechin polyphenols help control appetite and encourages the formation of the more healthy brown fat cells, and inhibiting fat absorption from the gut.  Blueberries and pomegranates are rich in phenolic acids and anthocyanidins, which have been shown to switch on fat metabolism and encourage weight loss even when the same number of calories are being eaten. 

Extend the overnight fast. The greatest evidence for fasting comes from research that studies a large cohort of women who had completed breast cancer treatments. They discovered that those who adopted early dinners and late breakfasts, leaving 13 hours between the meals (without intermediate snacking), lost significantly more weight, had lower levels of glycated Hb (a marker of diabetes) and lower inflammatory markers. What’s more, after five years, they had a 36% lower risk of breast cancer recurrence. 

In conclusion, avoiding diabetes will reap enormous benefits for overall well-being, the risk of chronic disease and early death. Restricting calories with an unpalatable diet is only a short term solution and rolling out the soup and shake diet is likely to be expensive. As well as keeping the weight down and eating less sugary foods, it is important to be aware of the other long term factors such as improving gut health, eating phytochemical rich foods, extending the overnight fast and exercising on an empty stomach.