This is probably a good time to mention that while I have practiced intermittent fasting consistently for the last year, I'm not fanatical about my diet. I work on building healthy habits that guide my behavior 90% of the time, so that I can do whatever I feel like during the other 10%. If I come over to your house to watch the football game and we order pizza at 11pm, guess what? I don't care that it's outside my feeding period, I'm eating it.
What time period works best? Keeping your eating window earlier—say, from 7 a.m. to 3 p.m.—seems to be the most beneficial. The body’s biological clock is primed to eat earlier in the day, explains Courtney Peterson, PhD, assistant professor of nutrition at the University of Alabama at Birmingham. “In most people, blood sugar control is best in the morning and gets worse as the day progresses. You also digest food faster in the morning. So there’s a metabolic advantage to eating earlier in the daytime,” she says.
Also, if you eat a big dinner the night before, I think you’ll be surprised by how much energy you have in the morning. Most of the worries or concerns that people have about intermittent fasting are due to the fact that they have had it pounded into them by companies that they need to eat breakfast or they need to eat every three hours and so on. The science doesn’t support it and neither do my personal experiences.
The 5:2 diet is another intermittent fasting method, which allows you to eat normally five days a week and restricts your calories to just 500 to 600 for the other two days. The advantage of following the 5:2 diet versus the 16:8 diet is that you can eat normally on any days you want, depending on your schedule. However, research shows that the 5:2 diet isn't more effective than continuous calorie restriction.
Wearing jeans to work wears away your belly. University of Wisconsin researchers found that people who wore denim to work took almost 500 more steps (about a quarter mile) throughout the day than they did on days when they wore more formal attire. Sure, you may feel more dapper in your suit, but losing extra belly fat is sure to make you see jeans in a different light and feel more confident—no matter what you’re wearing.
IF as a weight loss approach has been around in various forms for ages, but was highly popularized in 2012 by BBC broadcast journalist Dr. Michael Mosley’s TV documentary Eat Fast, Live Longer and book The Fast Diet, followed by journalist Kate Harrison’s book The 5:2 Diet based on her own experience, and subsequently by Dr. Jason Fung’s 2016 bestseller The Obesity Code. IF generated a steady positive buzz as anecdotes of its effectiveness proliferated.
“Tahini is an oft-forgotten option for nut and seed butters, but it sits front and center in my fridge because it delivers major creaminess to sauces and smoothies and packs a powerful flavor punch,” says Willow Jarosh MS, RD co-owner of C&J Nutrition. “Although some advise against eating the spread because of its high omega 3:6 ratio, the super high intake of omega-6s in the average American’s diet isn’t due to things like tahini—it’s mostly from not eating a variety of fats or consuming the majority of fats from fried foods and packaged snacks. As long as you’re also eating foods rich in omega-3s, your end-of-day ratio should be nothing to worry about. Plus, tahini is loaded with tons of healthy nutrients like copper, which helps maintain anti-inflammatory and antioxidant responses in the body. It also provides 6 percent of the day’s calcium in just one tablespoon.”
Those issues can be part of what's known as the “keto flu,” Warren says. Other side effects of the keto diet, all of which are tied to carb withdrawal, can include lightheadedness, nausea, mental fog, cramps, and headaches, in addition to tiredness. Luckily, the keto flu doesn't usually last more than a week—which is coincidentally about when people start to see the number on the scale go down, says Warren.
When your body burns its stores of fat, it can be hard on your kidneys. And starting a ketogenic diet -- or going back to a normal diet afterward -- can be tricky if you’re obese because of other health issues you’re likely to have, like diabetes, a heart condition, or high blood pressure. If you have any of these conditions, make diet changes slowly and only with the guidance of your doctor.
In practice, however, I would be concerned with eating enough. Based on my experience, teaching yourself to consistently eat more is one of the harder parts of intermittent fasting. You might be able to feast for a meal, but learning to do so every day of the week takes a little bit of planning, a lot of cooking, and consistent eating. The end result is that most people who try intermittent fasting end up losing some weight because the size of their meals remains similar even though a few meals are being cut out each week.
While all fruits are healthy, a handful of them reigns supreme when it comes to frying fat and de-bloating your belly. University of Kentucky researchers found that eating watermelon can lower fat accumulation, while another group of great minds discovered that honeydew can banish water retention and bloating. Spend ten minutes chopping up these slimming fruits for the week ahead. Enjoy them solo as a snack, throw them into yogurt or add them to salads. Watermelon is also one of these 50 Best Foods for Him—in Bed—share them with the man in your life.
As a lifestyle-leaning research doctor, I needed to understand the science. The Obesity Code seemed the most evidence-based summary resource, and I loved it. Fung successfully combines plenty of research, his clinical experience, and sensible nutrition advice, and also addresses the socioeconomic forces conspiring to make us fat. He is very clear that we should eat more fruits and veggies, fiber, healthy protein, and fats, and avoid sugar, refined grains, processed foods, and for God’s sake, stop snacking. Check, check, check, I agree. The only part that was still questionable in my mind was the intermittent fasting part.
It all depends on you. Researchers suspect that the 16:8 diet isn’t quite as effective for weight loss as more extreme forms of fasting, like alternate-day fasting. On the other hand, studies suggest that alternate-day fasting doesn't produce better weight loss results compared to daily calorie restriction. Plus, eating only every other day is very restrictive and can be tougher to stick to.
Understanding the potential adverse effects of intermittent fasting is limited by an inadequate number of rigorous clinical trials. One 2015 review of preliminary clinical studies found that short-term intermittent fasting may produce minor adverse effects, such as continuous feelings of weakness and hunger, headaches, fainting, or dehydration. Long-term, periodic fasting may cause eating disorders or malnutrition, with increased susceptibility to infectious diseases.
Lose It! This two-week phase is designed to jump-start your weight loss, so you may lose up to 6 to 10 pounds (2.7 to 4.5 kilograms) in a safe and healthy way. In this phase, you focus on lifestyle habits that are associated with weight. You learn how to add five healthy habits, break five unhealthy habits and adopt another five bonus healthy habits. This phase can help you see some quick results — a psychological boost — and start practicing important habits that you'll carry into the next phase of the diet.