DEAR DR. ROACH: My adult son has lost over 100 pounds on an intermittent fasting diet (16 hours fasting per day) and now wants to continue fasting in the morning and just eat a heavier lunch and dinner to maintain his new weight. I am not sure that this kind of long-term fasting is good for his health. For his meals, he eats anything he wants and counts his calories. I have told him that it is better for his health if he eats more of a Mediterranean-style diet, which would include a plate made up of mostly vegetables, a small amount of meat, grains and some good fats. Could you advise us what you think is a good way to maintain weight loss after being on an intermittent fasting diet? — G.B.
ANSWER: Most of the studies on intermittent fasting use an alternate-day approach, where a person takes in very little food (25% of needs) on fast days and more (125%) on the intermittent “feast” day. The studies show effective weight loss, similar to those put on a calorie-restricted diet. There aren’t as many data on a 16-hour daily fast.
My experience is that intermittent fasting is an effective strategy for some people in whom other strategies have been unhelpful. One of my colleagues, an expert in weight loss, calls intermittent fasting another tool in her box.
While I agree with you that a Mediterranean-style diet has many health benefits, your son has had success with his fasting strategy. I have seen over and over again people having success with their plan (whatever that plan might be), only to go back to their old dietary habits and have the weight come back on. I would recommend he continue with the intermittent fasting, continuing to count calories, but to try to make sure what he does eat is as healthy as possible.
DEAR DR. ROACH: In a recent column, a reader was concerned about his enlarged prostate and possible UTI. You wrote that he may possibly benefit from changing the pH of his urine, but you did not specify which way. It implied that acidic urine could be a problem. However, doesn’t the drug Hiprex given for recurring UTIs help prevent infections by making the urine acidic? — J.B.
ANSWER: Methenamine (Hiprex) is converted in an acidic environment (a pH below 5.5) to ammonia and formaldehyde. Formaldehyde is not an antibiotic, but does have general bacteria-killing effects. Hiprex also contains two organic acids, hippuric acid and mandelic acid, which help keep the urine pH low so the drug will work. Other physicians prescribe vitamin C in addition to help ensure an acidic urine.
So, it’s not the acidic urine that kills the bacteria with methenamine, it’s that the drug is converted to bacteria-killing formaldehyde in the acidic urine. Most bacteria are relatively resistant to the acidic pH changes that are possible in the urine.
Methenamine is not an oft-used treatment. The antibacterial effect of the formaldehyde is weak compared with antibiotics. You are correct that it is most commonly used to prevent infections rather than to treat them. I have given it in women who have had allergies to multiple antibiotics.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected] or send mail to 628 Virginia Dr., Orlando, FL 32803.