Researchers recruited 49, pre-menopausal women whom were non-habitual breakfast eaters, meaning they regularly ate breakfast less than 2 times per week.
Participants were then placed in 1 of two groups:
The study itself was a month long and participants were required to have a dietary food recall on random days of the week, for a total of 10, 24 hour food recalls.
Prior to, during and after the completion of the study, various body weight measurements were taken to understand the effect of breakfast skipping or eating on body composition.
Weight and Body Composition
The breakfast eating condition group observed a .06 ± .08 kg increase in body weight over the course of the 1 month study, which was statistically significant compared to their baseline weight (graph below).
Interestingly, the group which continued to skip breakfast observed no significant difference compared to their baseline measurements.
If that's not surprising enough, the breakfast eating group actually increased their fat mass as well by approximately 0.5 ± 0.6 kg, almost entirely matching the body weight increase.
The breakfast eating group ended up increasing their total calorie intake by 266 ± 496 (!) per day, whereas the breakfast skipping group did not show any significant difference in their food intake.
Issues with the study
Regardless of the study, there are always little things that reduce the validity.
First, dietary food recalls are tough. It's really difficult to determine if the individuals are actually telling the truth.
That being said, the increase in food intake reported by the breakfast eating groups certainly explains the weight gain.
Otherwise, I don't have very many issues. They also gave individuals an accelerometer (fitbit-esque) to track their activity levels, which could potentially explain weight loss or gain. Fortunately, there was no real difference between their typical activity levels and each group.
But how could this be? Breakfast is the most important meal of the day!?
Truth be told, that notion is bullshit. The only way I could ever stand behind that statement is if the breakfast is primarily protein (which almost never happens for normal people. Need carbs for energy, right!?).
Some studies indicate that skipping breakfast does in fact lead to weight gain. Problem is, that has a lot to do with people, who are already overweight and can't control themselves later in the day.
Now that is certainly a problem, and I totally understand that. But if you're taking people who are
1. Over weight,
2. have issues controlling themselves regardless and
3. Now you're adding in even more calories; of course they are going to begin gaining weight.
The problem is that the breakfast they are consuming is carbohydrate heavy, and probably doesn't do anything for their feelings of satisfaction. So they consume more calories and then don't have any significant reduction in calories from other meals for the rest of the day.
That equates to.. you guessed it.. an increase in body weight.
That's the thing. This idea of NEEDING to eat breakfast, regardless of if you're hungry, only really helps if it means a reduction in TOTAL calorie intake, via the rest of the meals throughout your day. If it doesn't then you're just adding in extra calories which means, weight gain. End of story.
Additionally, and even though this is tough to say definitively, your circadian rhythm plays a large role in how you respond to food.
As i've mentioned before in toher articles, hunger and suppression of appetite is largely regulated by when you typically eat. Ghrelin (the hunger hormone) is secreted in response to when you normally eat. Additionally, it's no surprise that hormones which are released in response to eating, also act on a similar schedule.
When you through a monkey wrench into this system, like having breakfast for instance, you can begin to have an adverse response to food, which can result in weight gain.
Don't believe me? Take a look at this post discussing the adverse reactions hormonally regarding forcing yourself to eat breakfast when you normally don't (2).
These people being studied not only gained weight from eating breakfast, but they were also hungrier after wards, had higher blood glucose and higher insulin levels. On their own, that's not a giant issue (insulin isn't always bad) but chronically, it can present an issue. It's even worse if these individuals are overweigh/obese and already have a bad insulin and glucose profile.
So how can I use this information?
The main problem is when people just assume that having any breakfast will automatically equate to weight loss.
If these studies are any indication, doing so won't (unless you do it right as outlined above).
Calories, first and foremost matter the most, regardless of if you consume breakfast or not. If eating breakfast means you'll increase your calorie intake, then you'll gain weight. Period.
Why this should matter to you
It should matter because it's another nail in the coffin for the bullshit argument that breakfast is essential for health. (It isn't).
Next time someone tells you it is, you'll understand that breakfast will only benefit an overweight individual if it is protein heavy and results in a reduction in total energy intake throughout the day. Simply eating any old breakfast doesn't magically mean you'll lose weight.