Sunday, September 4, 2016

Eating Your Largest Meal for Lunch, Instead of Dinner May Have Real World Weight Loss & Health Benefits | Guest Post

You better super-size that lunch box if you plan to enjoy the scientifically suggested health and body weight benefits of getting the lion's share of your energy intake at lunch, instead of dinner [15%, 50%, 15% + 15% (ideally) healthy snacks].
This is one of the rare occasions when SuppVersity articles need an introduction before the introduction. Why's that? Well, in contrast to 99.9% of the other 2280 SuppVersity articles the following text wasn't written by myself, but by my good friend Alex Leaf. How's that?

Well, as Alex is going to point out in the next paragraph. He was the one who spotted the latest "meal timing" study and I thought that Alex's at least as qualified as I am. He's, after all, an important contributor to the Examine Research Digest (always the articles that need the least editing ;-) and a registered general and sports nutritionist with his own business, while I am just... well, a physicist. "So why don't you let him do the work and get the credit," I thought... and he delivered. The only thing I had to do was to add this intro and reformat the article so that it would fit into the SuppVersity blueprint. Enjoy!
Meal timing and meal frequency are different things, but related:

Grazin' Bad For the Obese!

Breakfast Keeps You Lean?!

Regularity is Key to Leanness

Optimal Meal Freq. 4 Kids?

8 Meals = Stable, But High Insulin

Are 6 Meals Better Than 2?
So, a couple days ago I shared a study on my Facebook wall suggesting that eating the majority of calories at lunch, rather than dinner, leads to greater weight loss and improvements in insulin sensitivity (Madjd et al, 2016). For whatever reason, Adel asks that I write a guest post on it for SuppVersity. And how could I deny that request ;-)

I felt that this study was amusing and worth the coverage (and apparently Adel agrees) because there is a lot of controversy surrounding meal timing and macronutrient distribution throughout the day. Perhaps it started with Kiefer’s book, The Carb Nite Solution, about a decade ago, but there is this persistent belief that stuffing your face at dinner is ideal for weight loss. I know that Adel has written about at least three studies on this topic (here, here, and here).

Personally, I’m of the opinion that there are many successful ways to eat, and the most important aspect is the sustainability of the program for you. After all, if you don’t adhere to whatever weight loss diet you are following, you won’t make progress. But who cares what I think, let’s get on to the study at hand.

The study design was relatively simple: randomize 80 women with obesity (average age of 34 years) to a comprehensive weight loss plan where one group eats most of their calories at lunch (LM group) and another group eats them mostly at dinner (DM group).
“Groups were separated into subjects who had their main meal at dinner (DM) and subjects who had their main meal at lunch (LM). Subjects were assigned to consume 15% of their energy intakes at breakfast and 15% of their energy intakes with their snacks, with either 50% of daily energy intake at lunch and 20% of daily energy intake at dinner (LM group) or vice versa (DM group).”
After 12-weeks, both groups showed significant reductions in body weight and improvements in blood lipids and glycemic control. However, the LM group showed significantly greater reductions in body weight (additional 1.42 kg of weight loss, or 0.12 kg per week), fasting insulin, and HOMA-IR (a measurement of insulin resistance) than the DM group.
Figure 1: Relative change in selected anthropometric, blood glucose and lipid management markers (Subar et al, 2015);
the asterisks * indicate statistically significant difference between groups (p < 0.05).
If you study Figure 1, the message it sends appears to be clear: Gorging at lunch is better than gorging at dinner, right? Well, that is certainly one possibility. Ultimately, however, we have to ask why the LM group lost more weight before trying to make general statements like that. The food logs showed no differences between the groups, i.e. neither in terms of their total energy nor their individual macronutrient intake - at least if you believe what the participants reported eating, anyway (Subar et al, 2015).
Who the f*** wrote this article, it sounds less "SuppVersity" than usual!? Even if you skipped the introduction you may have noticed that the way the article is written differs from your average SuppVersity post.

That's (as people who read the introduction would know ;-), because it is guest post #2 by my friend Alex Leaf, who has recently turned his passion for nutrition, training and supplementation into a profession and opened his own business, Leaf Nutrition - obviously not before amassing a range of titles from certified personal trainer to the Master of Nutrition and certifications as nutritionist from the state of Washington and the International Society of Sports Nutrition. Future coaching requests should thus better go to Alex than me, after all, he has the time, the education and the patience to work with clients I have never had (those of you who asked me if I do coaching will know that).
And when we are already talking about reporting, let's segue into adherence right away: It is, after all, possible that eating a larger meal at lunch led to greater satiety and thus greater dietary adherence, possibly by reducing snacking and caloric intake throughout the day. Maybe the DM group simply didn’t report those early morning and/or afternoon snacks they secretly ate to keep their hunger under control. Albeit purely speculative, this assumption is not without support from previous research showing that when people eat more food at night, they eat significantly more food that day overall (de Castro, 2004).

Alternatively, both groups were instructed to gradually increase physical activity as part of the comprehensive weight loss program, so perhaps a larger lunch gave more energy to be active during the day and therefore expend more energy. Eventually, however, we will probably never know to which extent this "messed" with the results and as Adel agreed on the respective Facebook thread it may eventually be a strength of the study.
Alex's bottom line: Whatever the actual reason for the advantages the scientists observed may have been, the study at hand has one huge strength going for it – it was conducted in free-living women (Madid et al, 2016). Someone on Facebook commented that this study should be disregarded for that exact reason – too uncontrolled and too much confounding they said. I disagree. As a nutritionist myself, these types of studies provide invaluable practical relevance to me because they mimic what could happen if I were to give similar advice to my clients.

SuppVersity Suggested Classic: Less Frequent Large(r) Meals Increase Your Energy Expenditure 24/7 x 365 and  Conserve Your Resting Metabolic Rate While Dieting for Fat Loss | more
Importantly, instructions to eat larger meals at lunch or dinner were part of a comprehensive weight loss program (I’ve said this three times now, so it must be important). The participants received personalized dietary advice from a dietitian whom they met with twice per week and talked with on the phone daily. There was a lot of involvement and motivation coming from the outside.

As such, we can’t conclude that eating more at lunch has benefits over eating more at dinner without the guidance of a nutrition professional, although previous research by de Castro (2004) would suggest that large dinners have a particularly negative effect on daily total energy intake, too.

Also keep in mind that the differences between groups were modest, at best - shifting the focus from dinner to lunch is thus not going to be the game-changer that turns an obese couch potato into a jacked Olympian. Speaking of which: For people who train in the PM, the results may obviously have looked completely different. So the last word on meal timing and dinner vs. lunch being the optimal time to eat your largest meal has certainly not been spoken, yet | Comment!
  • Madjd A, Taylor MA, Delavari A, Malekzadeh R, Macdonald IA, Farshchi HR. Beneficial effect of high energy intake at lunch rather than dinner on weight loss in healthy obese women in a weight-loss program: a randomized clinical trial. Am J Clin Nutr. 2016; pii: ajcn134163. [Epub ahead of print]
  • Subar AF, Freedman LS, Tooze JA, Kirkpatrick SI, Boushey C, Neuhouser ML, Thompson FE, Potischman N, Fuenther PM, Tarasuk V, Reedy J, Krebs-Smith SM. Addressing current criticism regarding the value of self-report dietary data. J Nutr. 2015; 145(12): 2639-45.
  • de Castro JM. The time of day of food intake influences overall intake in humans. J Nutr. 2004; 134(1): 104-11.