Intermittent fasting: Good or bad?

Dear Alice,

During the day, I keep a strict paleo diet and end eating at 10PM and Begin eating at 12 PM the next day. Around 10:30 AM the next day, I do full a body weight training session and begin eating at 12 PM. Basically, I only drink water during my fast or keep calories to a five calorie maximum. After the fast, I eat whatever I want (paleo that is). I'm trying to get my body to use excess fat as energy, therefore causing me to lose body fat and gain muscle faster. I feel great and I have witnessed fast results, (increased strength and leanness) within a month and half of intermittent fasting. My question is do you think intermittent fasting is unsafe? Or just a new an effective way to see increased health?

Dear Reader,

It’s terrific that you're paying attention to your health and feeling good about the results you're seeing. You’re certainly not the first person to see results with a paleo diet (which entails an eating plan with little to no processed food and a greater emphasis on fruits, vegetables, and nuts) and you’re also not only one who's tried intermittent fasting (IF), or eating within strictly defined windows of time. However, the jury’s still out about the answers to your questions. There just haven't been many studies aimed at investigating long-term safety and effectiveness of IF — and there is even less on the combination the practice with a strict paleo diet. That being the case, read on for more on what is known about the two dietary practices.

Taking a look at paleo diets: there is evidence that suggests that this way of eating does have some health benefits. For example, people who follow paleo diets report losing body fat and their lab results often show improved blood glucose levels, glucose tolerance, lower blood pressure, and lower blood lipid levels — all of which are risk factors for diabetes and other chronic health conditions. So, if you were previously eating a diet rich in carbohydrates, fats, and processed foods, you may see your health take a turn for the better by switching to a paleo diet. 

However, paleo diets might not be for everyone — a high protein/low carbohydrate diet can put extra stress on kidneys, which may be a concern for those with kidney conditions. Some people with a rare genetic condition called hemochromatosis may be susceptible to iron buildup in their organs. It's advised that meat and fish consumption be limited for those living with the condition and eating a paleo diet. For folks considering a paleo diet who live with chronic conditions such as heart failure or diabetes (type I or type II), it's best done under the guidance of a medical professional to avoid a sharp drops in blood pressure.

With regard to IF, there are a few other considerations to keep in mind. In terms of your physical health, intermittent fasting isn't necessarily harmful to your body. Calorie reduction, achieved by this practice, could benefit your waistline. However, it's been noted that some folks may eat more than they intended when they break a fast, thereby counteracting the desired effects. Another consideration is making sure that the food you do eat provides adequate vitamins, minerals, and protein. Keeping this practice in moderation is also key as taking fasting to the extreme can contribute to malnourishment.

What seems to be of real concern, though, is whether fasting for any length of time is practical for the average person. Eating on a very strict schedule may affect your relationships and impact your life more broadly. For example, meal times are often inherently social and there is much to be gained in terms of quality of life by sharing meals with friends, family, and acquaintances. Imagine turning down breakfast with a grandparent or being on vacation with a friend and saying “no, I can’t eat with you until the afternoon”— it could be a missed social opportunity, right? Thinking about how IF may impact your well-being as well as your health is certainly a worthy consideration.

No matter what foods you eat or when your meals take place, keep in mind that while losing a few pounds can be healthy for some people, losing too much weight too quickly or losing too much body fat can be unhealthy for others. As such, framing your goals in terms of optimizing health may be the ticket for determining the best regiment for you. However, before you make too many drastic changes, it's wise to talk them over with a health care provider or registered dietician. S/he can help to inform dietary changes and assist you in reaching your health goals in the safest way possible. For more information healthy eating and weight management, check out some additional Q&As in the Nutrition and Physical Activity category in the Go Ask Alice! archives!


Originally published Nov 06, 2015

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