Is intermittent fasting safe during pregnancy?
For healthy pregnant women, fasting does not appear to increase major risks such as preterm birth or low birth weight, but fatigue and dehydration are real complaints. If you have diabetes or are early in your pregnancy, discuss fasting with your doctor first.
Fasting during pregnancy reduces average birth weight by approximately 94 grams. This is statistically measurable, but clinically negligibly small. The risk of a baby being born genuinely underweight, below 2,500 grams, does not increase. Preterm birth also does not occur more frequently in women who fast.
There is one exception that deserves attention: fasting specifically in the first trimester appears, in one study, to be associated with a much larger drop in birth weight, namely an average of 353 grams. This finding stands alone and has not yet been confirmed in other studies, but it is a reason for extra caution early in pregnancy. The same study found that a higher-fat diet outside fasting hours may have a protective effect on birth weight, although that too is not yet well substantiated.
For the mother herself, the most clearly documented risks are fatigue and dehydration. In addition, there are preliminary indications that fasting may affect the results of prenatal check-ups: reduced fetal movement, reduced amniotic fluid volume, and lower scores on the biophysical profile. These findings come from a limited number of studies and require confirmation.
For pregnant women with diabetes, fasting is genuinely inadvisable. During fasting hours, blood sugar drops to dangerous levels, while after breaking the fast it rises sharply. Physicians currently explicitly advise pregnant women with diabetes against fasting.
Too little is known about the long-term health consequences for the child. Studies examining this are of low quality, and firm conclusions cannot be drawn. Always discuss any doubts about fasting during pregnancy with your midwife or doctor.
This answer is based on multiple summaries of studies, including a review of dozens of individual studies and studies involving thousands of pregnancies. In every case the research is observational: no study was able to directly establish cause and effect, because women were not randomly assigned to a fasting or non-fasting group. The finding regarding the first trimester comes from a single study, and the findings on diabetes come from only five small studies. The researchers rated the quality of the evidence on long-term outcomes for the child as low to very low.
Can you remove microplastics from your blood vessels?
There is still too little research to answer this question.
Which supplements are risky in the presence of kidney damage?
Yes, multiple supplements are demonstrably risky in the presence of kidney damage. Herbal preparations (particularly those containing aristolochic acid), germanium supplements, and high doses of vitamin D or C stand out the most; if you already have kidney problems, discuss every supplement with your doctor.
Does the Wim Hof method actually work?
The physiological mechanisms behind the Wim Hof breathing technique work against you rather than for you in the cold: hyperventilation disrupts the CO2 balance and suppresses the body's own protective responses, causing core temperature to drop faster rather than slower.
Is intermittent fasting safe if you have type 2 diabetes?
Intermittent fasting can be safe in type 2 diabetes, but only if you do this in consultation with your doctor, because your medication will almost always need to be adjusted to prevent blood sugar from dropping too low.
Does fasting or intermittent fasting help prevent cancer?
There is no evidence that fasting prevents cancer in humans; the animal results are promising but contradictory. If you want to address excess weight as a way of reducing risk, intermittent fasting can be a tool for that, but do not expect a direct cancer-preventive effect.