There's been lots of debate about whether certain meal patterns are better for weight loss than others. While some argue that sticking to three squares a day – without snacking – is the best way to control intake and prevent over-eating, others claim that having five to six "mini-meals" is a better way to go to keep one's metabolism running and hunger levels at bay. The latter approach, sometimes called "grazing," has clearly caught on with an increasing number of Americans. In fact, national survey data suggest that a grazing-type eating pattern has become the new norm, with about two-thirds of American adults snacking two or more times daily in addition to meals.
• Grazing may increase risk for developing bacterial overgrowth. When bacteria replicate excessively in the small intestine, it results in a condition called Small Intestinal Bacterial Overgrowth. As anyone who's had SIBO can attest, the condition produces a variety of miserable symptoms, from bloating and diarrhea to nausea and constipation. Once it develops, SIBO must be treated with antibiotics in order to be eradicated.
When the body is fasted, the muscles in the small intestine produce a periodic wave of forward motion called the migrating motor complex. This cleansing wave is a housekeeping function – not unlike the sweep of a broom – that prevents stasis of intestinal contents. Thus, bacteria passing through don't have time to settle in and lay down roots.
The intestines need to be fasted for at least 90 minutes at a time in order for routine cleansing waves to occur. So if you're prone to stretching out your meals over the course of a few hours – say, taking a few nibbles at a time while you work and multi-task – there's a reasonable chance you'll never go a full hour and a half without food passing through your small bowel. People who have a history of SIBO – or other risk factors for the condition, such as chronic use of acid suppressing medications or pancreatic insufficiency, may want to consider whether giving their gut a break for a few hours each day may be of benefit.
[Read: Digestive Enzymes: Help or Hype?]
• Grazing may not be optimal for people prone to constipation. Ever notice that you often find yourself needing to visit the loo within an hour of having a particularly large meal? It's not a coincidence. Chalk up that experience to an involuntary nervous system reflex called the gastrocolic reflex, which instigates forward movement (peristalsis) in the colon after being triggered by one of several different stimuli.
At the top of the list of triggers is physical distension of the stomach. The stomach has mechanical receptors that detect stretch. Significant stretch after a large volume intake or bulky meal – say, an entrée-sized salad, a large tub of popcorn or a Thanksgiving meal – sends a strong signal to the colon, essentially telling it to make room for the load of food that's about to head down the pike. (Higher caloric loads, such as those associated with traditional meals, also trigger the gastrocolic reflex.) For people who tend toward constipation, then, consolidating their food volume into fewer eating occasions can leverage the gastrocolic reflex and maximize their chances for a post-meal movement. Conversely, nibbling small amounts throughout the day may not produce enough stimulating stretch of the stomach or enough of a caloric load to trigger the gastrocolic reflex.
• Grazing may result in eating too close to bedtime. To be sure, I generally advocate for making lunch the main meal of the day, and downgrading the traditional large dinner to a lighter affair – some soup or salad, perhaps an omelet with some veggies. But if you find that your mini-dinner is chased by perpetual grazing throughout the evening until bedtime, you may be setting yourself up for acid reflux as the result of lying flat with a too-full stomach. The digestive tract, after all, is not immune to the effects of gravity.
If you experience heartburn while trying to fall asleep – or wake up with a sour taste in the mouth, a scratchy throat or excessive coughing – examining your nighttime eating patterns may be worthwhile. For most people, it's best to stop eating two hours before bedtime – and three full hours if you have chronic acid reflux – to allow your stomach time to fully empty before lying down flat. If hunger strikes within that two- to three-hour zone, however, I often recommend a liquid snack like a small yogurt or fruit smoothie, or a glass of milk; it will exit the stomach relatively faster than solid food. Staying upright while eating and after meals – rather than slumped on the couch – can also help prevent reflux, as can using a wedge pillow to keep the entire torso elevated in bed.
If you're a card-carrying grazer and find this pattern of eating to be well-tolerated digestively and helpful for maintaining your desired weight, then by all means, carry on! But if you're a grazer with room for improvement in the digestive department, it may be worth considering a different approach to your daily diet.
[Read: Foods That Cause Bloating.]
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Tamara Duker Freuman, MS, RD, CDN, is a registered dietitian whose NYC-based clinical practice specializes in digestive disorders, celiac Disease, and food intolerances. Her personal blog, www.tamaraduker.com, focuses on healthy eating and gluten-free living.