Ketonuria and Smelly Urine: The Many Ways Ketones Can Make Your Pee Smell
High Protein, Low Carb Diets

Eating a diet high in protein puts your liver to work. As your liver processes the extra protein you've taken in, it produces ammonia as a by-product. Since ammonia is toxic, your liver converts it to urea...
Eating Disorders
The eating disorders Anorexia and Bulimia can cause stinky urine in a couple of different ways. One way is from starvation causing an excess of ketones in the blood. In the case of bulimia, repeated vomiting may also contribute to foul smelling urine...
Starvation
Starvation can cause the body to go into ketosis. The above-average level of ketones in the blood may cause stinky urine.
Fasting
Fasting, like starvation and eating disorders, can cause your body to go into ketosis. While fasting, you may notice that your urine smells bad. The reason is that your body is eliminating ketones from your blood, and they don't smell very good...
Glycogen Storage Disease
Glycogen storage disease type 1, or GSDI or von Gierke disease, is a genetic disorder. That means that if your parents or grandparents had it, you may be at risk. It starts early, when you’re still an infant, and it can lead to problems with growth later in life.
Renal Glycosuria
Renal glycosuria is a very rare inherited disease, estimated to affect just 0.16-6.3% of the population. Although the condition is benign, which means that people who have it don’t have many problems, it can make your urine smell bad.
Pregnancy and Lactation
Hormonal changes during pregnancy or lactation can cause stinky urine. However, another possible reason you are noticing extremely smelly urine while you're pregnant may be the changes in your own sense of smell...once again, due to hormones.
Repeated Vomiting
C'mon...you don't want to see a photo for that, do you? Have a daisy instead.
Hyperthyroidism
Extreme Stress or Illness
There are many ways that extreme stress or illness can cause stinky urine, but the most common is the change in your body's hormones. Your body may start operating differently under extreme stress, causing all sorts of problems, including smelly pee.