There are many ways to support healthy metabolism. Two major ones that have gotten a lot of attention recently are Intermittent Fasting (IF) and High-Intensity Interval Training (HIIT). The best news is that both of these are relatively simple to do, can be free or cheap to implement and can be used together!
IF is also referred to as “time-restricted eating.” In it, you choose an 8-hour window each day to eat and then consume no calories the rest of the day. This gives your body an extended fasting period where it has to mobilize resources (burn fat). Over the course of thousands of years, humans never had ready access to food the way we do now. Even just 50 years ago, most people ate three square meals but did not snack throughout the day. Now we commonly eat three meals AND snack through the day. We’ve increased our caloric intake in a time when most of us are more sedentary than ever.
Human beings evolved amazing mechanisms to weather good times and bad times. Our metabolism is such that we store excess calories as fat during times of abundance and can burn those stores to survive periods of famine. During feast times, insulin stores extra sugar in the blood as fat. Many of our modern meals are carb-rich – essentially flooding the body with quick energy. When the body is overwhelmed with resources it can’t use immediately, it is smart and saves much of those calories for a rainy day. Insulin also impairs cognitive function which is why many people report feeling more mentally alert while intermittent fasting. During the 16 hour period of fasting, the body has to burn those stored calories as fuel. It releases glucagon (insulin’s hormonal opposite) which mobilizes excess fat in the body.
Intermittent fasting can be effective even if only utilized 5 days out of the week. Many patients still have great results and can ease their time restriction on the weekend. It’s still a good goal to eat during a 12 hour window on your “off” days. It is helpful to ease into intermittent fasting. Start with a 12 hour fasting window and every day or two add an hour to work up to a 16 hour window over the course of 1-2 weeks. If you are a brittle diabetic, pregnant, under 16, over 70, have chronic kidney disease, chronic heart disease or a history of eating disorders, this may not be the best food strategy for you. These patients must be sure to consult a healthcare provider before starting IF.
High-Intensity Interval Training – (HIIT) involves a short workout alternating periods of “work” and “rest” or high and low intensity. This may be done with just about any activity – weights, kettle bells, jump squats, jumping jacks, any type of cardio (running, biking, swimming), etc. Most HIIT workouts last between 4 and 20 minutes. Many cardio cycles involve 30 seconds of high effort and 30 seconds of rest (or light effort) – commonly done by alternating sprinting and jogging or cycling hard and then lightly. HIIT can also involve doing an exercise like jumping jacks for 45 seconds followed by 15 seconds of rest. One style of HIIT called Tabata involves 20 seconds of work and 10 seconds of rest for a duration of only 4 minutes.
HIIT has garnered a lot of scientific study recently and has many proven benefits. HIIT is great for busy individuals because you can get the same benefit of a moderate-intensity 60-minute cardio session with a HIIT cardio session of only 20 minutes. Short sessions are much easier to fit into our busy schedules. HIIT may even be better at targeting fat cells than doing a traditional or “steady state” cardio session. HIIT can be done in the gym or at home and requires little to no special equipment. HIIT principles can be applied to any type of exercise to prevent getting bored with your routine.
HIIT and IF are a great combination to boost metabolism and fuel healthy weight loss. Eating a healthy diet is also crucial to supporting healthy metabolism. Dr. Keating gives individualized health recommendations that include dietary modification. Baseline blood work is also a good idea to rule out any underlying metabolic disorders. Call for a visit today so we can assess the whole picture and help you with your weight loss journey!