Years before it became fashionable, I recommended to my patients interested in optimizing their heart health not only to eat their last meal at least 4 hours prior to bedtime but to also keep their dinner meal light (for more details see “Heal Your Heart…” below).
As a researcher involved in numerous fat-feeding studies, it is well established that after we eat a meal containing fat, our triglycerides levels (blood fats) not only increase but can spike upwards of 2-3 fold with peak levels occurring ~4 hours after the meal. Similarly, consuming carbs leads to a rapid rise in blood glucose and insulin levels that taper down over the next several hours (in the absence of insulin resistance). The rise in blood glucose levels tend to be slower after consuming complex carbs contained in dietary fiber than in processed and refined carbs found in soft drinks (soda) and candy. However, if you keep your dinner meal light and engage in mild physical activities (such as an after dinner walk), you will boost your metabolism by revving up proteins involved in digesting fats and carbs thereby maintaining triglyceride, glucose and insulin levels under better control. Left untreated, high levels of blood fats, glucose and insulin promote weight gain, insulin resistance, hypertension, diabetes as well as raise the risk of a heart attack and stroke.
It turns out that intermittent fasting (IF) can also help to boost metabolic (and vascular health) because increasing the number of hours in the fasting state reduces weight, blood pressure and blood levels of triglycerides, glucose and insulin. For example, in a recent study of men at increased risk of diabetes, eating for 6-hours a day improved insulin sensitivity and blood pressure without increasing the urge to eat. Keep in mind that a 6-hr time window for eating may be quite difficult especially if you work long hours; my most successful patients adhering to this regimen also have more flexible schedules. That is, they generally eat breakfast ~10 AM and conclude their dinner meal ~4 PM with weight loss in the 10-20 lb range (and in some cases more than 25 lbs). Because IF represents a lifestyle change rather than a fad diet, weight loss can be sustained for years. While many of my patients have found 6-hour IF to be too restrictive, they are able to maintain an 8 and especially 10 hour eating period (e.g., ~8 AM- 6PM) daily. Whatever IF approach you decide on, the majority of calories should be consumed during breakfast-lunch followed by a light dinner with no snacking afterwards.
In addition to weight loss, my successful IF patients tell me they sleep better, have more energy, are happier and more productive. Even though it can be very effective, make sure to speak to your physician and determine whether IF is an appropriate lifestyle consideration for you.
Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine in Baltimore, Maryland USA. His book: “Heal Your Heart: The Positive Emotions Prescription to Prevent & Reverse Heart Disease” focuses on natural ways to improve your heart and emotional health.