A new study surveyed more than 4,000 adults ages 40 to 54 about their breakfast habits and then checked them for heart attack risk factors. The researchers found that people who eat a large percentage of their total daily calories for breakfast have the fewest heart attack risk factors, while those who skip breakfast are more likely to have plaques in their arteries and other heart attack risk factors (J of the Am Coll of Cardiology, Oct 2, 2017).
Several previous studies show that breakfast skippers are more likely to be overweight and to suffer from diabetes and heart attacks (Circulation, July 22, 2013). The researchers think that skipping breakfast may “serve as a marker for a general unhealthy diet or lifestyle, which in turn is associated with the development and progression of atherosclerosis.”
- 27 percent of the study participants reported that they ate a large breakfast (more than 20 percent of their daily calories)
- 70 percent ate a light breakfast (less than 20 percent of their daily calories)
- 3 percent skipped breakfast
The researchers used ultrasound to determine how much plaque these people had in the arteries in their bellies, necks and legs. They found increased plaque size and thickness in:
- 57 percent of those who ate a large breakfast
- 64 percent of those who ate a light breakfast
- 75 percent of those who skipped breakfast
Those who skipped breakfast also had higher BMIs (body mass index, a measure of fatness), greater waist circumferences (belly fat), higher blood pressures, higher triglycerides and higher fasting blood sugars (diabetes).
The authors found that people who skipped breakfast had lots of unhealthy habits and felt that their increased risk for heart attacks might be caused by all of their bad habits, not just skipping breakfast, so they adjusted their data to correct for smoking, drinking, cholesterol levels, waist circumference and daily intake of red meat and salt, as well as age and gender. Correcting for all of their unhealthful habits did not change the results. Unquestionably, skipping breakfast was associated with having bigger and thicker plaques in the arteries throughout their bodies.
Why a Big Breakfast May Improve Heart Attack Risk Factors
It is more healthful to move about after you eat than it is to sit still or go to sleep. Your blood sugar rises after you eat and high rises in blood sugar can increase risk for obesity, diabetes and heart attacks. A high rise in blood sugar causes the pancreas to release large amounts of insulin, which converts excess sugar to a type of fat called triglycerides that can be stored as fat in your body to make you fat.
Resting muscles use almost no blood sugar and what little sugar does go into your resting muscles requires insulin to do so. When you contract your muscles after you eat, the muscles lower your blood sugar levels by drawing large amounts of sugar into their cells, and they do not even need insulin to draw the sugar in.
Another possible explanation is suggested by a new study that showed changing the times of day or night that mice were fed affected the bacterial content of their colons and their weight (Am J Obstet Gynecol, Aug 2017;217(2):218.e1-218.e15). Many other studies have shown that the types of bacteria in the colon influence weight and other heart attack risk factors.
Most people are far more active early in the day and slow down late in the day, so people who skip breakfast are likely to take in their calories later in the day when they are sitting or even just before they go to sleep. The safest time to eat is when you are most active and that is usually earlier in the day. The least healthful time to eat is just before you go to bed at night. My breakfast is usually whole-grain cooked-breakfast cereal such as oatmeal or barley with nuts and fruit.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.
The problem with observational studies like this one is that they don’t show cause and effect, just association. To their credit, Dr. Mirkin did not say that skipping breakfast causes heart disease, and neither did the study authors. However, most people don’t get this distinction, and neither do the media who will report this as causal.
In this particular case, there are lots of other studies that show eating or skipping breakfast is not associated with health outcomes, and frankly, why would it? It is much more likely that because we have been told for so long that “breakfast is the most important meal of the day”, that people that follow this health advice generally lead healthier lifestyles.
I’m also curious how this ties into an IF (intermittent fasting) diet. It’s far easier for the bulk of the time one fasts to be in the morning. I practice IF and generally eat my last meal around or before 7pm. I go to bed around 10pm, and eat my first meal at 11pm (lunch time). How does this affect everything this study shows? I wonder if those who follow IF have a generally fitter lifestyle and are immune to “skipping breakfast” since our calories are also restricted (in most cases). We’ve only got 8 hours to eat all our calories, after all.
I know Dr. Mirkin is a proponent of IF as well. I’m curious about his take on this.