Now more than ever there are more diets, theories, programs and pieces of exercise equipment bombarding us every day. However, America continues to grow fatter and fatter every year3. Obesity is a major problem. There are numerous factors that play into gaining and losing weight such as activity level, cultural habits, genetics and so on.
However, probably the most influential factor is energy intake (i.e. eating). You can work your butt off in the gym day in and day out. Yet, you will never have that six pack if you overeat everyday on top of that.
In the fight for the next big money maker of fat loss miracles, there are two that have stuck around for quite a while now. Those are:
- Eat a good breakfast to "Jump Start" your metabolism.
- Don't eat late at night because everything you eat will be stored as fat.
What Is The Truth?
Both of these have of explanations and logical reasoning behind them, but regardless of how you come to the conclusion, they are, at the heart the same. But are they true? While it is true that the digestion of food does require energy and creates a thermogenic effect, the question at hand is if eating a breakfast in the morning results in a higher 24 hour energy expenditure or a negative net calorie balance.
The second theory that eating after a certain time (typically ranges between 6-8pm) results in the storage of every calorie that you eat. This is an interesting one that has perplexed me for quite some time. The notion that after 6pm our body alters the way that it processes nutrients is rather fascinating to me.
Somehow, for some reason, after 6pm the metabolic fate of all nutrients (especially carbohydrates) is to be stored as fat. These two little snippets of nutritional folklore have hung around longer than most others and this as driven me to get to the bottom of it all. So the pushing question here is, "Are they true?" Recent research1 has found the answer to both of them!
867 individuals consisting of both men and women were studied for there food intake at various time throughout the day for a number of days. Neither the subjects, researchers nor dietitians who analyzed the food for nutrient content were aware of which meals would be analyzed at what times of the day. This was done to prevent subjects from eating less/more or lying about actual intakes.
The food intakes were analyzed for density (calories per gram) and at what times of the day meals were eaten. The criteria for a "meal" was it had to be at least 50 calories and separated by 45 min from the previous food intake. They were also analyzed for a satiety index based on calories per minute.
This measure gives an idea of just how badly these people were stuffing themselves and at what times of the day. And as a side note, the average weight of the participants was 150 pounds, so no these were not already overweight people who were accustomed to overeating.
The First Point:
The results were interesting to say the least. The first major point was that as the day progressed meal size increased and the time between meals decreased. So people were eating more, more often! This is where the satiety index comes in.
For what ever reason people seem to feel more and more hungry as the day wears on and of course will eat until they are full. You know the old bodybuilders adage - You never want to go hungry!
The Second Point:
The next point made actually helps to answer the question about getting in a good breakfast. There was a very strong and negative correlation between meal size early in the morning and meal size late at night. That means people who ate meals with high energy content in the morning were eating less total calories the rest of the day, and vice versa. The people who didn't eat much in the morning actually ended up eating more the rest of the day.
Between 6pm and 11pm calorie intake per meal skyrocketed from 525 calories to a whopping 720 calories per meal. And remember, people were eating more meals more frequently at this time. Not only that, but the calorie density shot up.
So these people are eating high calorie, low volume / weight food. These are the people that always tell you that they don't eat much but can't seem to lose weight. On top of that, during that same time period carbohydrate intake shot from 35 grams per meal to 72 grams per meal. That is more than double!
This suggest that people tend to underestimate just how many calories they are eating and that is probably a direct result of feeling hungrier and hungrier as the day wears on. Many things can affect hunger, not just how much food is actually in your stomach. The things we see and smell, a phrase, someone just talking about food. All of these things can make you hungry. And the more time that has passed in the day only give more chances for one of those to pop up and make a person hungry.
There You Have It...
So there you have it. We have answered out two pressing questions. Does eating breakfast "Kick Start" your metabolism? No, the reason that eating breakfast can be a factor in a structured weight loss program is because you will tend to eat less calories over the course of a day. And our second questions, does restricting food past a certain time (especially carbohydrates) prevent a person from getting fat? Again, no it doesn't.
For what ever reason the overall calorie density of food that people choose to eat at these times of the day skyrockets. And more over, the foods that people seem to reach for seem to be carbohydrate rich. If one were to cut the carbs after 6pm, you just taken a big chunk out of your total calorie intake.
Add that to a good breakfast in the morning and you are likely to eat even less during the day. A lower total calorie intake over the course of a day, month or year is not a magic metabolic formula for fat loss. It is just another way to get you to eat less.
In today's modern world the average length of an individuals day has increased dramatically. Before the invent of the simple light bulb much of the days activities were over by sundown. Now we are up through all hours of the night. For most people, being up doesn't always involve being active.
There are many people who sit up watching late night infomercials thinking how they should get that new piece of exercise equipment and get back in shape while they munch on some delectable snack. The bottom line here is pretty simple. It's not the carbs, its not the time of day.
There is no magic ratio, combination or super pill that will make you thin. It comes down to being absolutely sure you know the exact number of calories you are putting into your body everyday.
- De Castro JM (2004). The Time of Day of Food Intake Influences Overall Intake in Humans, J. Nutr. 134: 104-111
- De Castro, J. M. (1987) Circadian rhythms of the spontaneous meal pattern, macronutrient intake and mood of humans. Physiol. Behav. 40: 437-466.
- Mokdad, A. H., Serdula, M. K., Dietz, W. H., Bowman, B. A., Marks, J. S. & Koplan, J. P. (1999) The spread of the obesity epidemic in the United States, 1991-1998. J. Am. Med. Assoc. 27; 282: 1519-1522.