It’s a figure as uncompromising as the average Briton’s: obesity is now costing the UK almost £100billion a year. Analysis from the Tony Blair Institute published last week described the “sick and impoverished nation” our excess weight is creating, amounting to four per cent of the GDP – that has seen an additional 6kg added to men’s waistlines over the past decade, and 5kg to women’s.
The report is “absolutely shocking”, Roy Taylor, professor of medicine and metabolism at the University of Newcastle, says of the “desperate situation” the UK is now in. When he qualified as a doctor in the mid-’70s, seven per cent of adults had a body mass index over 30 (deemed obese); now, that figure has near-quadrupled to more than 25 per cent, with a further 37.9 per cent considered overweight. “We’re just far too heavy, just now, as a population.”
This is not so much a matter of individual choices, Taylor adds, but our “obesogenic environment” – in which sedentary lifestyles and abundant high-calorie foods have become the norm. If you’re looking to shed that extra 6kg, here are four ways to do it in four weeks.
Why it works
While the introduction of the Atkins diet in the ’60s was long dismissed as a fad, research has since shown the weight loss potential of lowering carb intake – with a review of existing literature this year noting that ‘several notable studies have suggested that low-carb diets are efficient in body mass lowering.’ A 2018 study published in the British Medical Journal also found that among overweight patients, those who cut carbs and replaced them with fat meant their metabolism increased and a greater number of calories burned daily than those who undertook a high-carb, low-fat diet.
Carbohydrates such as white bread and pasta drive up glucose levels in the blood, which the body stores as fat if surplus to requirements. By reducing the amount of carbohydrates consumed, should prompt the body to burn stored fat for energy, resulting in weight loss – along with “a wealth of other health improvements,” says Saira Hameed, consultant endocrinologist and author of The Full Diet, including the potential to reverse Type 2 diabetes, and improve the body’s regulation of glucose.
How to do it
Hameed advocates a plan that is “lower carbohydrate, moderate protein, no ultra-processed food and eating healthy fats and good amounts of fibre” (unsaturated fats such as fish, nuts and seeds and whole grains, beans and leafy vegetables respectively).
Protein generates “the strongest ‘fullness hormone’ response from the gut which then signals satiety to the brain,” Hameed explains. “Protein also tastes good and is usually very versatile – things like a lamb ragu with a sprinkling of parmesan or a goat cheese omelette.” On a low-carb, high-protein regime, losing 6kg in a month “is a doable target”.
Why it works
Intermittent fasting is among the most-studied modern eating patterns – typically narrowing down consumption to within eight hours or less per day. (Time-restricted eating is a subset of this, which typically calls for a window of consumption within daylight hours.) The success is thought to be down to the fact that, with fewer hours in which to eat, less can be consumed, leading to a reduction in caloric intake. “Research shows that shorter eating windows (4-6 hours) produce the most weight loss because they result in the most energy restriction,” says Krista Varady, professor of nutrition at the University of Illinois, who has been studying intermittent fasting for two decades. “Individuals tend to cut out 500 to 600 calories per day when they eat in these smaller eating windows.”
Jason Fung, nephrologist and author of The Complete Guide to Fasting, adds that “in recent years, it has become popular to eat all the time [or] ‘graze’… Fasting is effective because it signals the change over from storing calories to burning calories.”
How to do it
The most common form of intermittent fasting is the 16:8 – a 16-hour fast, with an eight-hour eating window – where eating typically begins at midday and ends at 8pm. Or, the OMAD, which stands for one meal a day. “The longer fasts are more powerful, and generally done less often,” Fung says, “but this is personal preference.”
Varady agrees that individual choice should be the biggest factor in choosing fast type and length, but notes that “we know that people are more insulin sensitive in the morning (i.e our bodies can put away blood sugar into cells easily in the morning). Insulin sensitivity decreases over the day, and is lowest at night.” For that reason, “it’s better to place that eating window earlier in the day (8am-4pm) because that can help reduce diabetes risk factors such as fasting glucose, fasting insulin, insulin resistance.”
Why it works
Put simply, “the way that people lose weight is by reducing the amount of energy that they consume,” says Nick Finer, former honorary clinical professor at the University College London Institute of Cardiovascular Science. As such, diets that centre around calorie shedding work, as evidenced in a 2021 paper in the Journal of Obesity & Metabolic Syndrome, which deduced that ‘reducing daily calorie intake is the most important factor for weight loss.’ But maintaining calorie-cutting over the long term is hard to sustain, so works better for a finite period with a defined weight loss goal.
How to do it
“To lose a kilo, or 2.2lb of weight, you need to cut around 7,000 calories from your diet,” Finer explains. Others choose “fast days” – typically eating normally for five days of the week, and consuming between 500-800 on the remaining two.
Tempting as it may sound, stunts like the Twinkie Diet – where a professor lost almost two stones (12kg) in 10 weeks eating only ultra-processed snacks instead of regular meals (a plan high in sugar and fat, but low in calories) – are to be avoided. They may produce short-term results, but the overall effects on your health will likely be deleterious.
Why it works
In 2008, testing the hypothesis that dropping weight would reverse Type 2 diabetes, Taylor devised a plan to tackle what his patients explained were their biggest barriers to slimming: feelings of hunger, and the day-to-day challenges of making healthy choices. He designed a low-calorie liquid diet of shakes along with non-starchy vegetables (ie. salad greens) “free of troublesome decisions… it was surprisingly successful,” he says, resulting in a 15kg weight loss over the course of eight weeks.
That method is now the basis of the NHS’s Type 2 diabetes remission programme, and its efficacy has been borne out in numerous studies, including a 2019 meta-analysis from the University of Oxford, which found that ‘programmes incorporating meal replacements led to greater weight loss at one year than comparator weight loss programmes,’ and another, published in the Journal of the Academy of Nutrition and Dietetics in 2021, which showed that individuals who used meal replacements in over 60 per cent of their diet saw “the greatest effect on weight loss”.
How to do it
Taylor says that the most important first step to starting a meal replacement programme is both committing to it yourself, and ensuring your family and friends are on board – “because without that, it won’t work… you’ll find substantial opposition. I was very surprised that I came across this phenomenon, but it is very real”.
The next step is to find a liquid formula that suits the palate (popular versions on the market include Optifast and Exante): “there’s no magic to any one, except that it ought to be about 200 calories and in an individual packet” (to avoid needing to engage in deliberations over portion control). It is also important to find nutritionally complete meal replacements, which contain the requisite levels of protein, vitamins, carbohydrates, fats and minerals for good health.
Taylor recommends three meal replacements (be they soup or shakes, for eg) a day, plus unlimited salad greens during the requisite weight-loss period. After that, he suggests adding protein, such as chicken or salmon, to your salads to transition back to regular eating, and cutting daily food consumption by around a third, as “the amount that became habitual for [dieters] previously is going to be too much for their new, healthy, smaller body”.