A new study has taken a close look at what really happens inside the human body during a long water-only fast, and the results show both good and bad effects. The research involved 20 middle-aged people who didn’t eat any food for about 10 days, drinking only water, under close medical supervision. After the fast, they slowly started eating again with a healthy, plant-based diet for about five days.
Weight Loss and Physical Changes
Everyone in the study lost a lot of weight-about 7.7% of their body weight on average. Their waist size and body mass index (BMI) also went down. These changes lasted even after they started eating again. However, the fast wasn’t easy. Many people felt tired, had headaches, felt weak, or had trouble sleeping. A few even had more serious problems like stomach pain, low potassium, or irregular heartbeats.
How the Body Adapts
The researchers used advanced tests to look at over 1,300 different proteins in the blood. They found that about 6.6% of these proteins changed during the fast, but most of them went back to normal after people started eating again. This means that most of the changes from fasting are temporary.
Some of the proteins that dropped are important for keeping muscles and bones healthy. The body seemed to adjust by lowering certain hormones, possibly to protect muscles and bones when food is scarce. This is a smart way for the body to save energy and keep important tissues safe during tough times.
Switching to Fat for Energy
During the fast, the body switched from using sugar for energy to burning fat. This was shown by changes in certain blood proteins and hormones. The body started making more ketones, which are chemicals made when fat is broken down. This switch helps people survive when they don’t eat for a while and is one of the reasons why fasting can lead to weight loss.
Possible Brain Benefits
One surprising finding was that levels of amyloid beta proteins in the blood went down during the fast. These proteins are linked to Alzheimer’s disease, so lowering them could be a good thing for brain health. However, more research is needed to know if this really helps prevent memory problems in the long run.
Risks: Inflammation and Blood Clotting
Not all the effects were positive. The study found that fasting caused a spike in inflammation-a sign that the body’s immune system was working harder. Levels of certain markers like C-reactive protein (CRP) and other chemicals went up. There was also more activity in the blood that could lead to clotting. These changes could be risky, especially for people with heart problems, because they might increase the chance of heart attacks or strokes.
Are the Changes Permanent?
Most of the changes in the blood went back to normal after people started eating again. However, the temporary rise in inflammation is something doctors are concerned about, and it’s not clear if there could be any long-term harm.
What Does This Mean for You?
This study shows that a long water-only fast can help you lose weight and may even have some benefits for your muscles, bones, and possibly your brain. But it also comes with risks, especially increased inflammation and possible heart issues. Most of the changes are short-term, but because fasting can be hard on the body, it should always be done under medical supervision.
In summary, fasting for many days is a powerful tool that changes many things in the body-some good, some bad. If you’re thinking about trying it, talk to a doctor first to make sure it’s safe for you.
