Last Updated on: 11th September 2024, 02:43 pm
This article was written by Associate Registered Nutritionist (ANutr) Cherie Ko, and reviewed by Registered Dietitian, Sarah Idakwo.
Earlier this year, the success of the NHS “soups and shakes diet” program was announced, with plans to expand the program to more local health areas across the UK.
While much success has been reported in terms of weight loss and diabetes remission, little attention has been given to the psychological, behavioural, and mental effects of being on such a low-calorie diet for 12 weeks.
In this article, I will offer my perspective as an eating disorder dietitian on the NHS “soups & shake diet.”
Understanding the NHS Soups and Shakes Diet
The NHS “soups and shakes” diet is part of a type 2 diabetes remission program aimed at supporting individuals recently diagnosed with type 2 diabetes who are living with ‘obesity’ or are overweight (1). The program provides participants with nutritionally balanced, low-calorie meal replacement products (soups and shakes) for up to 12 weeks to ‘kick-start’ weight loss. Alongside the diet, participants receive support from healthcare professionals during the re-feeding process and the reintroduction of food into their diet.
Living on 800 Calories
In most weight loss programs, it’s recommended to reduce your daily intake by at least 500 calories, with advice not to fall below 1,200 and 1,500 calories for females and males, respectively. The NHS diet, however, cuts this down to just 800 calories a day—400 calories less for women and 700 calories less for men. To put this in perspective, the daily caloric intake recommended for a child is 1,200 calories.
Studies on this diet and other low-calorie programs suggest that these meal replacements are designed to provide all the nutrition necessary for normal body function, with about a third of participants achieving sustained weight loss (2). However, these studies focus solely on weight loss, neglecting the mental and emotional impacts of adhering to such a restrictive diet, particularly for individuals who have previously suffered from an eating disorder or are at risk of developing one.
The Psychological Impact of Extreme Calorie Restriction
Numerous studies have highlighted the negative psychological effects of food restriction and dieting (3). These include an increased risk of depression, emotional distress, and irritability during periods of starvation. Additionally, food restriction often leads to an intense preoccupation with food, with individuals structuring their day around meals and savouring each one (3, 4). Once food is reintroduced without restrictions, many report a loss of control and a compulsion to overeat (5).
The Minnesota Starvation Experiment
One of the most telling studies in this regard is the Minnesota Starvation Experiment, conducted during World War II. This study aimed to understand the effects of severe caloric restriction and to develop strategies for the rehabilitation of people who had experienced starvation (6). Thirty-six healthy men were placed on a diet of around 1,800 calories per day for six months — more than double the 800 calories recommended in the NHS program.
The results were profound. Participants experienced significant physical and psychological effects, including drastic weight loss, decreased basal metabolic rate, and extreme weakness. However, the psychological impacts were even more alarming. The men became obsessed with food, developing rituals around eating, and some even reported vivid dreams about food. Their mental health deteriorated, with many showing signs of depression, anxiety, and irritability. Social isolation became common, and some participants developed symptoms similar to those seen in eating disorders, such as binge eating when food was reintroduced.
This experiment starkly illustrates the dangers of severe caloric restriction. Even with a diet of 1,800 calories, more than double the 800 calories in the NHS program, the participants suffered severe mental and emotional distress, along with a long-term impact on their relationship with food.
The “Biggest Loser” Study
Another study that sheds light on the effects of extreme dieting is the research conducted on participants of the reality TV show “The Biggest Loser.” Contestants on the show followed a very low-calorie diet, often around 1,000 calories per day, combined with intense exercise, to achieve rapid weight loss.
A follow-up study conducted six years after the show, revealed that most contestants had regained a significant portion of the weight they had lost . But the most alarming finding was the persistent metabolic slowdown that occurred. Their resting metabolic rates had plummeted, meaning they were burning significantly fewer calories at rest than would be expected for their body size (7).
This phenomenon, known as “metabolic adaptation,” made it incredibly difficult for the participants to maintain their weight loss, even when they continued to follow healthy eating and exercise habits.
The study highlights the dangers of extreme calorie restriction: while weight loss may occur initially, the body adapts by slowing down its metabolism, which can lead to weight regain and make future weight loss efforts even more challenging. Additionally, the psychological toll of this type of dieting, including an increased focus on food and potential for disordered eating patterns, cannot be ignored.
An Eating Disorder Dietitians Take on Extreme Diets
I don’t deny that weight loss can positively impact health, Type 2 Diabetes, and other chronic diseases. However, is this extreme approach truly a realistic way to pursue overall health?
Chronic diseases, including Type 2 Diabetes, are complex and multifactorial. They are influenced by a web of factors — diet, genetics, stress, sleep, and physical activity. By focusing narrowly on weight loss as the singular solution or cure, we risk oversimplifying the issue.
More concerning is the potential for this approach to inadvertently promote weight stigma, implying that weight is the primary or only factor to address. This can reinforce harmful stereotypes and overlook the needs of patients in smaller bodies who also live with Type 2 Diabetes.
Are we doing them a disservice by not addressing the broader context of their health? In the rush to ‘fix’ the problem through extreme means, we might be missing the bigger picture — true, sustainable health that goes beyond just the number on the scale.
Are you currently struggling with weight loss and have tried many diets to no avail? Maybe it’s time to explore other options. Click here to book your free discovery call and learn more about sustainable approaches to weight loss.
