Eating Healthy is a Matter of Time!

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Last month, I wondered if the eating schedule had any impact on staying healthy. The conclusion at that time was a definite “We’re not sure…but it could!

I must revise this conclusion.

But first, let’s talk about food and metabolism.

Background

Eating makes our body burn calories. The cost of this burn is around 10% of our total daily metabolism. This phenomenon is known as diet-induced thermogenesis, or the thermic effect of food.

Our level of activity and energy varies along the day. This natural observation lead to the obvious question:  When we eat in the morning, do we burn the same number of calories than if we eat the same meal at night?

The answer is no. The thermic effect of food is higher in the morning than the evening. So is our metabolic rate. We also clear up blood sugar and substrates faster in the morning.

Several studies strongly suggest eating most of our intake late during the day increases the risk of obesity. [1]Consuming More of Daily Caloric Intake at Dinner Predisposes to Obesity. A 6-Year Population-Based Prospective Cohort Study [2]Timing of food intake predicts weight loss effectiveness

Furthermore, in one randomized controlled trial, investigators noted a high-calorie breakfast triggered  greater weight loss than a high-calorie dinner. [3]High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women.

However, this seemingly clear picture was muddled by two important studies. [4]Effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose. [5]The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial The first suggested that skipping breakfast and eating more later did not affect calories burning over 24 hour period. The second hinted that “skipping breakfast for 4 months has no effects on body weight in overweight and obese adults.”

This conclusion must be revised in light of new data. That’s science for ya: there are few constants except change, a commitment to lifelong learning and the obligation to humility.

Science doesn’t try to be “right” but less wrong over time.

~Unknown

Thus, in order to be “less wrong”, inquisitive minds interested in health in nutrition are reading this well designed study [6]Title: Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over study. done at U of Turin, Italy, by Broglio et al.

The Turin Study

How it was done

20 normal-weight men and women volunteers [7]As we wrote previously here, the controlled nutrition studies are forcibly small were randomly assigned to one of two groups:

Morning Group:  Standardized meal at 8 AM.

Evening Group: Same standardized meal at 8 PM.

Two weeks later, participants exchanged groups (cross-over trial). During the whole trial, participants were monitored for metabolic rate at rest, insulin, blood sugar levels, as well as free fatty acids before and after each meal.

The results

Three significant findings were reported:

  1. Early meals burned more calories. This is consistent with prior studies
  2. Free fatty acids blood levels, which are associated with propensity to develop obesity, were less influenced by the morning meal.
  3. Blood sugar levels, which are also higher levels associated with propensity to develop obesity. were less affected by the morning meal.

What it means

This well designed and rigorously performed study add weight [8]pun not intended :-D to the recommendation to avoid large meals in the evening. The exception to this rule could be [9]although the evidence is anecdotal at this point for those who practice intermittent fasting [10]If you truly love to geek nutrition science, help yourself and learn much more about IF here and here. 😀 combined with intense physical activity.

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References & Footnotes   [ + ]

1. Consuming More of Daily Caloric Intake at Dinner Predisposes to Obesity. A 6-Year Population-Based Prospective Cohort Study
2. Timing of food intake predicts weight loss effectiveness
3. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women.
4. Effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose.
5. The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial
6. Title: Is the timing of caloric intake associated with variation in diet-induced thermogenesis and in the metabolic pattern? A randomized cross-over study.
7. As we wrote previously here, the controlled nutrition studies are forcibly small
8. pun not intended :-D
9. although the evidence is anecdotal at this point
10. If you truly love to geek nutrition science, help yourself and learn much more about IF here and here. 😀