When You Eat is Important – if you want to lose weight

February 04, 2013

When You Eat is Important – if you want to lose weight 

 ReferenceInternational Jr of Obesity, Jan 29 2013 

 Breakfast like a King/Queen, Lunch Like a Prince/Princess, Dinner like a Pauper.  You’ve heard that.  Grandma knew it.  Now we have research to support it.  Dr. Garaulet from Spain was the lead author in collaboration with Harvard researchers interested in chronobiology – the timing of natural rhythms. Dr. Garaulet found 420 Spaniards who were interested in losing weight.  They were separated into two groups based on when they naturally ate their largest meal of the day.  Then, they were given some training on how to lose weight.  

Over the next five months, both groups ate the same amount of calories, which were carefully tracked.  Both had the same hormonal changes.   But one group lost 5 pounds more, or 25% increased weight loss.  That was the group that ate their largest meal at lunchtime, earlier than 3 pm.   Those who ate their largest meal later than three pm also tended to also skip breakfast more than the others.   

Now, it is culturally common in Spain to eat a big lunch and then a smaller dinner.  It is also not uncommon to eat the last meal very late at night.  The late eaters were very similar in all aspects from the early eaters except for their insulin sensitivity.  In that instance, they tended to be a bit more insulin resistant. 

 Why would this be the case?  We’ve actually known this for a long time in tiny pieces.  In America, we have had studies that show that if you eat a low glycemic breakfast you will eat 200 fewer calories later in the day.  We also know that there is a strong correlation between skipping breakfast and being overweight.  So there are clear indications that timing matters.  

What is that timing? Cortisol is our main chronobiological hormone.  It is called our “stress” hormone but that role may be overstated.  It is also the hormone that makes us feel alert and awake and helps us mobilize energy.  Hence, when we have stress we make extra energy available, which is a good thing.  Cortisol peaks at 7-8 am and reaches a low during the night at 4 am before surging at 530-600 am.  If you eat a big breakfast, you are matching your calorie intake with the main hormone your body is putting out to help mobilize energy.   

If you eat a large meal after 4 pm, you are taking in a lot of calories just when your “mobilization of calories” is winding down.  Hence, you might as well store them.  Considering that it takes a couple of hours for calories to work through your digestion and into your blood, it only makes sense to have those calories show up as you need them.  Now match that timing with healthy protein and vegetables, reduce the total amount and you lose weight. 

 WWW. What will work for me.  I sleep better when I let myself get used to not eating late at night.  That evening snack often disrupts my sleep later.  Many of us are late-night snackers.  We are shifting the burden of calories to the time our body wants to shut down, leaving it little choice but to store.

The column was written by Dr. John E Whitcomb, Brookfield Longevity, Brookfield, WI.