Before his passing, Michael Mosley, of “Trust Me I’m a Doctor” and fasting for weight-loss fame, offered words of caution, warning that the new GLP-1 drugs may not be the miracle solution they seem. Originally designed to treat diabetes, these medications affect the function of both the brain and the digestive system. Some evidence suggests they may have the potential to reduce compulsive behaviours beyond dietary habits, but they are increasingly being used to treat weight-loss resistant patients. However, this raises the question – are we endorsing a medication-based crash diet? (1)
Crash Diets and Their Dangers
Crash diets, often involving extreme calorie restriction and rapid weight loss, are known for their significant health risks. Without a significant shift towards nutrient-dense foods, cutting calories alone can seriously compromise overall health. Crash diets typically result in nutrient deficiencies, muscle loss, and long-term harm to metabolism. (2)
The Role of GLP-1 Inhibitors in Weight Management
GLP-1 inhibitors, like semaglutide (Ozempic) and liraglutide (Saxenda), are increasingly used for weight loss. These drugs mimic the GLP-1 hormone, which reduces appetite, slows gastric emptying, and stimulates insulin release. While they are effective for weight loss, they, like crash diets, can contribute to malnutrition by significantly reducing food intake. (3)
How GLP-1 Inhibitors Cause Malnutrition
GLP-1 inhibitors may cause nutrient deficiencies by suppressing appetite. Users report a reduction in hunger, which can drastically reduce their ability to eat, limiting calories but potentially also nutrients. Additionally, delayed stomach emptying can lead to nausea, vomiting, and diarrhoea, further negatively impacting nutrient absorption. (4)
Immediate Risks of Malnutrition
One of the primary dangers of GLP-1 inhibitors is malnutrition. When calorie intake is too low, vital nutrients like vitamins, minerals, proteins, and essential fatty acids are often under-consumed. Deficiencies in nutrients such as vitamin C and D, B12 and other B vitamins, as well as minerals such as calcium, iron, and potassium, can lead to fatigue, weakened immunity, impaired cognitive function, and muscle wasting. (5)
Muscle Loss and Metabolic Decline
A common consequence of malnutrition is the loss of muscle mass instead of fat. When deprived of calories, the body breaks down muscle tissue for energy, which slows metabolism and weakens the body. This ‘metabolic slowdown’ often results in weight rapidly returning to previous levels once normal eating resumes. This has been observed in those who stop using GLP-1 inhibitors – rapid fat gain with muscle mass remaining reduced. (6)
Mosley highlighted that muscle loss is especially dangerous for older adults. Sarcopenia, the age-related loss of muscle, increases the risk of falls, fractures, and reduced mobility. It also leads to a slower metabolism, making it harder to maintain a healthy weight, and increasing the risk of chronic conditions like osteoporosis and diabetes. A reduced muscle mass also impacts overall strength and endurance, impacting daily activities and reducing quality of life.
Cardiovascular and Psychological Risks of Malnutrition
Malnutrition can also cause cardiovascular issues by creating electrolyte imbalances, particularly with sodium and potassium, which are essential for optimal heart function. These imbalances can result in arrhythmias or even cardiac arrest. Inadequate essential fatty acid intake can also raise the risk of heart disease. (7)
The psychological impact of nutrient deficiencies includes increased irritability, anxiety, depression, and cognitive impairment, as the brain is deprived of the nutrients needed for optimal function. Severe nutrient deficiencies can exacerbate existing imbalances, and increase the symptoms and severity of many mental health conditions, from ADHD to severe mood disorders. (8)
Sustainable Health Over Quick Fixes
While GLP-1 inhibitors promise rapid weight loss, the malnutrition they can induce poses significant health risks. Deprivation of essential nutrients harms both physical and mental health, making this approach unsustainable and potentially dangerous. Sustainable weight loss through balanced diet and regular exercise remains the safest and most effective way to maintain overall wellbeing, and it is important to be aware of the risks that these medications pose to your health, especially without nutritional literacy and dietary changes.
(1) https://x.com/DrMichaelMosley/status/1680576877197492233
(2) https://www.obesityaction.org/resources/the-risks-of-the-crash-diet/
(4) https://www.guysandstthomas.nhs.uk/health-information/diabetes-medicines-glp-1-agonists
(5) https://my.clevelandclinic.org/health/diseases/22987-malnutrition
(6) https://pubmed.ncbi.nlm.nih.gov/35441470/
(7) https://bmccardiovascdisord.biomedcentral.com/articles/10.1186/s12872-021-02296-9
(8) https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626