Editor's Note: We like Dr. Lowery's Temporal Nutrition ideas. He seems to be really on to something with this 24-hour plan. Remember, Temporal Nutrition isn't a "diet," but an approach to eating which basically involves getting most of your carbs in the AM and most of your fats in the PM.
For those that need a refresher on the concept, here are the links:
An Exploration of Ideas
I'm a salty consumer advocate. Ask anyone I know, including the editors of this web site. Being such, I do my best to associate only with good people whether it's in academics, business, or personal endeavors. Likewise, I associate myself only with ideas and concepts that have both empirical and professional support.
So, I openly acknowledge that anything you read on Temporal Nutrition is an exploration of ideas: food for thought or perhaps a dietary tweak – nothing more at this time. It's an approach to eating for physique athletes and not meant for the obese or for diabetics (although the associated carb reduction may help to some extent.)
I'm happy to change my conclusions based on solid and repeatable new data like any good scientist would. Clinging to the same old beliefs and self-conceptualized (self-important?) plans is good marketing, not good science. So I'll leave that to the marketers and gurus.
Okay, I'm stepping off the soapbox (a little) and behind the virtual podium now. Let's discuss Temporal Nutrition. After a couple of years working with weight management groups ranging from overweight sedentary persons to athletes, I've come across a few time-of-day questions more than once. This article is a collection of these inquiries and "what ifs," in no particular order.
Remember, Temporal Nutrition isn't a system or a book or a video that I sell; it's just a logical way to approach eating that has encountered repeated success after casual analysis. I haven't heard about problems from anyone with whom I've worked.
But I'm also a critical thinker, being especially critical of my own theories. Remember, the nature of a think tank is to explore bleeding edge theories and possibilities while remaining unbiased and as close to legitimacy as possible. So, I offer this quote regarding time-of-day dietary manipulations:
The clinical implications of the 24-hour variations in glucose regulation for the design of meal schedules and therapeutic regimens that may optimize glycemic control in conditions of impaired glucose tolerance, jet lag, and shift work still need to be delineated.
– Van Cauter, E., et al. Endocrine Reviews 1997; 18(5): 716-738.
You may not be critically minded or patient enough to read the "Temporal Nutrition" articles, which could help you "learn to fish" (gain skills allowing you to choose lifestyle patterns for yourself). That's not overly surprising. Most people simply want the immediate gratification of being "handed a fish," however temporary the results may be. If you want to be told exactly what to eat, how much to eat, and when to eat it (all with a nifty "reader hook" about why it's the best), go buy yourself (yet another) diet book.
But I'll offer a wake-up call first. If you've spoken to authors and publishers as much as I have, one problem you'd see with these money-driven approaches is that the author needs to exaggerate why his/her system is "the one." Otherwise, he can't stand out in a glut of similar gurus. His sales and possibly livelihood depend upon it.
My goal is radically different. It's about education and physique, not sales. If you like another approach to dieting and it works for you (analyzing your long term numbers as much as your feelings), great! Go spend as much on it as you deem necessary. I'm sincerely glad you found something that's compatible with your genetics and lifestyle. If you're still searching for an educated and free approach, however, read on.
On to the questions!
Q: Is this around-the-clock style of eating about some esoteric notion of "food combining"?
A: Nope. Truth be told, the human body is well built to consume mixed meals, that is, protein and carbohydrates and fats together: P+C+F. It's true. We can readily absorb about 90-95% of the various macronutrients. That's darn good.
In Temporal Nutrition, carbs and fats are simply put into their most advantageous time blocks during a given day, and proteins are justifiably ever-present. We want carbs to end up as muscle glycogen, right? Then eat them in a planned fashion, mostly throughout the morning and the peri-workout period (the time surrounding your training.) It's pretty straight-forward.
We also want to stave-off evening cravings when most of us "fall off the wagon," right? Then it's logical to consume filling/satisfying fiber, protein, and healthy fats rather than a quart of orange juice or a pound of pasta during "couch time" in the evening.
Q: Will this approach to eating help me move toward a healthier lifestyle?
A: I don't know, but based on client feedback from those who've experimented with it, it's likely.
And I can't discount what I've seen in my own personal wellness efforts. Temporal Nutrition is a biologically-aware way to keep your mind on healthy food choices at the right times. Think of all the examples of refined starches deep fried in fat that won't fit into this AM/PM thinking.
By keeping an eye on your undeniable circadian rhythms and frequent meals, a man (or woman) remains conscious of his eating habits without worrying about hunger or obsessive portion control and eventual diet failure. We can eat quite a lot when it's done properly (oatmeal, whole fruits, vegetables, lean meats, low-fat dairy, etc.)
I like this notion, especially for bodybuilding men. I don't think that obsessively eating tiny portions of our favorite no-no foods works very well. I've said it before: What kind of freaky masochism is that?
Q: How necessary is this? Is it a diet plan?
A: It's not meant to be. Real diet planning by a dietitian takes many individual needs, including financial, social, medical, and lifestyle factors into account. There are entire academic textbook chapters on the subject. It takes a lot of time to do properly and it's highly individual just like a real diet assessment is. Hence, diet planning isn't the same as what we see in many commercial diet books.
Therefore, Temporal Nutrition is just a collection of metabolic and behavioral tweaks that have been incorporated into many diets. It's only meant to stack the odds in a dieter's favor. Whole food choices and total energy balance (EBAL) are paramount. Anyone who says otherwise is selling something.
Q: How strict should I follow AM carbs and PM fats?
A: Strictness is up to the individual and his/her results and ability to comply. For starters, just putting the preponderance of (low-glycemic) carbs earlier in the day – and say, limiting them after lunchtime – may be advantageous. And it's a more moderate and behaviorally sane alternative to very low carbohydrate diets.
On my three or four non-exercise days each week, I personally keep it down to about 50g CHO (50 grams of carbohydrates) between my afternoon snack, dinner, and supper and have no problems. This gives me a good feeling, but carb intake isn't zero. This way, a lower-carb intake is do-able, even in our grain-based world. In fact, I tend to eat nuts and vegetables instead of bread and pasta nowadays.
Let's face it, moderate carbohydrate reduction for one evening – knowing full-well that tomorrow morning will bring some low-glycemic-index carbs – is a far cry from jonesing for carbs all week. Carb jonesing is what's common on a typical low-carb diet and it results in potential overcompensation on a weekend (or simply falling off the wagon). Remember, we must think "long haul habits" not "diets" per se.
Regarding dietary fat, we know we need about 25-35% of kcal from fat, or about 80-110g daily for a male. We need it to maintain Testosterone levels, proper fat "burning," certain beneficial nutraceutical effects, etc. When we limit AM fats, we still need a time block in which to consume them. PM hours are what's left.
So, suggesting a reasonable intake of afternoon/evening fats (say, 30 grams per meal) is mostly just a method for reducing their negative effects on earlier (normally beneficial) carbohydrate metabolism while gaining the benefits of those 80-110g per day.
Why don't we care as much at night? Because carb metabolism is pretty lousy in the evening anyway according to multiple published studies, as we explored in the original Temporal Nutrition article. It's science, not just me. In fact, here's a quote:
Early work reported decreasing glucose tolerance in the evening and at night with evidence for insulin resistance at night. Subsequently an endogenous circadian component was described for glucose and insulin. Plasma triacylglycerol (TAG), the major lipid component of dietary fat circulating after a meal, also appears to be influenced by both the circadian clock and sleep time with higher levels during biological night.
– Morgan, L., et al., Chronobiol Int 2003; 20(5): 795-808.
Of course, one could take a more severe approach and simply attempt to eliminate all non-exercise-related carbs (relying on P+F meals), but then many of us are back to staring at stale saltine crackers as if they were glorious, golden sticky buns.
So, to recap, consuming dozens of grams of fat in the morning interferes with glucose tolerance for much of the day. (And there's more to it than that, beyond the scope of this Q and A.) I wouldn't recommend it and neither do large healthcare authorities.
If full, glycogen-replete muscles sound good to you (and they should), the morning hours are a big addition to the traditional post-workout period. Avoiding carbohydrate before lunchtime, while consuming glycogen-meddling fat is risky. We just can't exercise constantly to compensate for this problem every single day without risking overtraining.
The effects of heavy morning fatty meals are troubling to me, considering that about 20 percent of Americans are already experiencing syndrome X (i.e. metabolic syndrome: glucose intolerance with excess body fat, higher heart disease risk, etc.) So, keeping fats down to about 10 grams per meal, for breakfast and second breakfast, is usually achievable.
Lunch is pivotal. It could include a little more, perhaps 15-20 grams of fat, as your carbohydrate intake is reduced somewhat. (See, mixed meals aren't evil.) Or it could be entirely low-carb or entirely low-fat for those who want to cut either of these back even harder.
One note, however: circulating fats are normally higher in the evening and the triglyceride (TAG) response to a meal is indeed higher at this time. Hence, 30g of fat at an early dinner and again at supper should be plenty. (We did consume some morning fat by default and that's okay, even helpful.) We don't want to worsen cardiovascular risk with very large PM meals and resulting TAG concentrations, just as we don't want them to mess with our carbohydrate handling earlier in the day.
Q: How does Temporal Nutrition help compliance with all-important individual meals?
A: Let's think about it. It's often easier to find healthy, fast and/or portable carb and protein choices in the morning (e.g. oatmeal with fresh fruit and protein powder, fiber-rich cereals with skim milk, whole fruits, high fiber breakfast bars and a thermos of skim milk, legitimate protein bars, cottage cheese with fresh fruit, etc.) than to fry-up a lot of fat. We want to keep the AM carb choices slow-acting and moderately sized unless exercising, of course.
Similarly, dinner time is a great time to eat lean meats and olive-oil sautéed fibrous veggies. I don't think I want vegetables or grease in the AM, do you? Plus, the food focus remains on "when," not necessarily "how much." This keeps failure and guilt out of the picture. Food is a simple pleasure of life, not your enemy.
Q: I've heard elsewhere about P+F (protein plus fat) in the morning. Is this only for bulking? I'm up to the mid-teens in body fat percentage fat after following this.
A: I can't really speak for those who sell these kinds of diet systems or books. I think you'll find that most medical nutrition authorities recommend lower-fat breakfasts, for kids and adults.
I was just reading a 2005 paper suggesting whole grains and low-fat dairy for breakfast. (Rampersaud, G., et al. JADA 2005; 105(5): 743-760.) There are multiple reasons for this. Part of my own interest in lower-fat mornings is that they prevent high circulating fats in the blood, which are known to interfere with carb metabolism all the way through lunch time.
Will exercise change this effect? Probably some, but a diet plan that relies on constant exercise isn't really a diet plan per se, is it? And there's more to this low-fat, higher-carb AM thinking, too. For example, high-fat breakfasts aren't as satisfying, according to research done back in 1996. Unsatisfying breakfasts aren't helpful for dieters.
Rather than in the morning, I prefer to consume protein with healthy fats and less carbs in the evening because 1) That's when blood lipids are higher anyway, and 2) That's when dietary carbs don't enter muscle readily anyway (again, unless you just worked out). To me, consuming fat in the morning is more harmful than helpful. Carbs appear to be the better AM choice.
Waiting to consume carbs later, at a time when they don't readily enter muscle tissue, isn't good use of nutrient partitioning. Of course, if someone trains hard every single night (which I wouldn't recommend), then he's compensating for this natural phenomenon.
Q: I heard somewhere that I should eat carbs in the evening. Is this true?
A: Again, I can't speak for anyone who'd tell you that, but he may have a solid reason. Perhaps it has to do with minor and lingering next-day effects – or just marketing value.
I prefer less carbs in the evening, as I've said. Maybe I just can't get around the 30-50mg/dl higher blood glucose readings (to a standard meal) that are seen in the evening vs. the morning, as those evening carbs remain partly "trapped" in the bloodstream. To me this just can't be good.
My continued support of this conclusion isn't based on catchy marketing or ego. You see, I'm not the only one noticing potential metabolic problems with high evening carbs. Here are some quotes, the first on the consequences of evening carb intake and the second on the potential benefits of reducing them:
...high nocturnal glucose and insulin concentrations would lead to a reduction in fatty acid oxidation [less fat burning]... Fatty acids in the liver may then have been driven toward esterification [increased fat building] and thus new triacylglycerols would form, which would be exported to the plasma as VLDL triacylglycerol. Fasting fatty acid concentrations were also suppressed after the high-carbohydrate meal, a further probable effect of high nocturnal insulin concentrations. Insulin significantly affects lipase activity, serving to lower circulating fatty acids. [blunted fat breakdown] Hormone sensitive lipase would be suppressed, reducing the quantity of fatty acid liberated from adipose tissue. Furthermore, adipose tissue lipoprotein lipase activity would be increased by insulin, which would favor the uptake of fatty acids into adipose tissue for triacylglycerol storage.
While on the other hand...
After the high-fat evening meal, it's likely that plasma fatty acid concentrations would have risen because of the spillover from triacylglycerol lipolysis and the liberation of fatty acids from adipose tissue. [increased body fat breakdown/ extraction] In the absence of significant insulin concentrations, circulating fatty acids are likely to have undergone ß-oxidation. [fat burning] This theory is supported by the higher 3-hydroxybutyrate concentrations observed in the fasting state after the high-fat evening meal.
– Robertson, M., et al. Am J Clin Nutr. 2002 Mar;75(3): 505-10.
Overall, these data are persuasive. And when we consider that an entire, relatively new condition has been created called "night eating disorder," which is related to higher carbohydrate intake and fat gain, Temporal Nutrition becomes even more convincing.
Carbohydrate intake, especially in the PM hours, is a problem for many of us. It's little wonder that legitimate healthcare authorities have long-followed the "plate sectioning method," which aims to control the amount of starch on your plate. (So, I'm not alone in this thinking.) The version below is an old school approach used by nutritionists in Idaho that I believe was originally Swedish:
I'd like to also comment on the consequences of evening carb intake and suppression of growth hormone secretion (especially among men, who enjoy about 2/3 to 3/4 of their daily GH output early during early sleep). It's not helpful. Still, I'm not satisfied that evening fats would be any better in this regard.
You see, although it's long been known that dietary carbohydrate interferes with non-exercise GH secretion, I've also seen data that fatty acids do, too. The difference is that fats keep up your precious Testosterone levels, whereas carbs do little in this regard. And Testosterone acts synergistically with GH – amazingly so according to some information shared with me by renown researcher Kevin Yarasheski at a conference a few years ago.
GH alone is grossly overrated for muscle gain. But, if you're one of the people who are really into GH, you may want your last fatty meal to be consumed by 7-8 PM (depending on your bedtime).
Q: You're recommending a few hundred grams of carbs? I thought that carbs made people fat.
A: This depends on non-exercise physical activity (NEPA) level, gym time, family history, total hours of quality sleep, stress, division of meals, coffee/stimulant intake, etc.
It's true that some of us don't need many carbs. That's why I think it's best to limit them in the evening. What's a minimum amount? We can base it on several things. Regarding hormonally driven metabolic rate, the much more active form of thyroid hormone, triiodothyronine (T3), can be maintained with just 50g or more of daily carbohydrate according to some published research. Although not much, this is amplified by a need for about 100-150g daily to stay out of full blown ketosis.
Now, ketosis isn't as dangerous for a healthy person as it is for a diabetic, but it's a struggle to maintain for many persons – especially with kids in the house or without spousal support. Plus the brain demands glucose and forcing it into a state of ketotic adaptation (similar to starvation in some ways) is only a partial solution.
Athletes pose an even greater need .We active people need carbs for muscle glycogen replacement (even stored fat "burns in a carbohydrate flame") as well as for performance, fatigue resistance, a general sense of energy, and dietary variety.
If I had to put a gross number on it, I'd say that a carbohydrate intake of 40-55% of total calories is a reasonable range for many weight lifters
Q: Does exercise fit in?
A: Yes. It's the great corrector as far as body composition and performance are concerned, so much so that it's what some "diets" actually rely upon for their results.
Although the AM/PM thing attempts to address daily rhythms regardless of exercise, there are two things that will help. First, pre-breakfast moderate (non-panting) treadmill work or brisk outdoor walking can be done for 45-60 minutes. It's barely even exercise from an athlete's perspective but it works very well with low waking insulin concentrations.
This moderate, pre-breakfast exercise is direct, fat-specific loss that's mild enough to be done almost daily if need be. I like it for bodybuilding purposes; it's like reverse nutrient partitioning within the body – but in this case it's tissue specific "wasting". And it's not just for physique athletes; mainstream weight [fat] control strategies use it too:
Exercise programs of low to moderate intensity, long duration and high frequency seem to be most beneficial, with the most popular forms of exercise being walking/jogging, cycling and swimming.
– Grubbs, L. Nurse Pract. 1993 Apr;18(4): 20-2, 25-6, 29.
This direct attack on stored body fat also works well with the prior evening low-carb/higher fat meal, as any lingering effects would further enhance body fat vulnerability. The non-panting cardio would also set you up nicely to best-use the morning carbs to come during breakfast, second breakfast, etc.
Consuming a half scoop of protein powder with your java or tea upon waking might put your mind at ease regarding muscle loss paranoia. (Amino acids can help reduce the effects of high waking cortisol.)
Second is the obvious exercise: weight lifting. When done in the afternoon or evening, it creates another, even more muscle-specific "carb window" to accompany the natural AM one. Although hard workouts can't be done daily for very long (overtraining can manifest in as few as six days!), it's necessary for muscle growth/preservation.
Weight lifting even augments glucose tolerance in unique ways that we don't see with aerobic-only training. You might consider limiting intensity techniques like "negatives" (forced eccentric contractions) to every-other-week, however.
Conclusion: Stacking the Metabolic Deck
And so ends the more common questions. Truth be told, human biology is messy and somewhat open to interpretation. That's why Temporal Nutrition may not tickle everyone's fancy. That's okay. What many readers could use, however, is a real, tailored nutrition assessment from a qualified, licensed professional.
If you don't like his personality or counseling, dig around for a referral and carefully select another – just as you would with a second opinion from a physician. This would clear up a lot of the confusion that you might develop reading gurus' books and how they go about their mock assessments. The art and science of a real nutrition assessment is comprehensive and medically (and legally) accepted.
Whether you choose a guru or a licensed dietitian with experience in your situation (diabetes, athletics, obesity, etc.), remember that total kcal balance and whole food choices are paramount. The effort of Temporal Nutrition is to simply stack the metabolic cards in people's favor with biological rhythm tweaks. Or perhaps it's just something to consider as you learn as much as possible about your options.
In fact, although I don't sell a "system" like many gurus, I think you'll find far more evidence for Temporal Nutrition and the diets that compliment it than for many diet theories you'll see!
References and Further Reading
1. Baehr, E., et al. Individual differences in the phase and amplitude of the human circadian temperature rhythm: with an emphasis on morningness-eveningness. J Sleep Res. 2000 Jun;9(2):117-27.
2. Baily, S. and Heitkemper, M. Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects. Chronobiol Int. 2001 Mar;18(2):249-61.
3. Ballard, F. Restricted nutrition and protein turnover. J Hum Nutr. 1978 Aug;32(4):245-52.
4. Conley, M. and Stone, M. Carbohydrate ingestion/supplementation or resistance exercise and training. Sports Med. 1996 Jan;21(1):7-17.
5. Facchini, F., et al. Effect of iron depletion in carbohydrate-intolerant patients with clinical evidence of nonalcoholic fatty liver disease. Gastroenterology. 2002 Apr;122(4):931-9.
6. Franco, C., et al. Visceral obesity and the role of the somatotropic axis in the development of metabolic complications. Growth Horm IGF Res. 2001 Jun;11 Suppl A:S97-102.
7. Frape, D., et al. Effect of breakfast fat content on glucose tolerance and risk factors of atherosclerosis and thrombosis. Br J Nutr 1998 Oct;80(4):323-31
8. Harris, M., et al. Prevalence of diabetes and impaired glucose tolerance and plasma glucose levels in U.S. population aged 20-74 yr. Diabetes 1987 Apr;36(4):523-34
9. Huang, T., et al. Overweight and Components of the Metabolic Syndrome in College Students. Diabetes Care 2004; 27:3000-3001.
10.Kanaley, J., et al. Cortisol and growth hormone responses to exercise at different times of day. J Clin Endocrinol Metab. 2001 Jun;86(6):2881-9.
11. Langkilde, A., et al. Nutrients excreted in ileostomy effluents after consumption of mixed diets with beans or potatoes. I. Minerals, protein, fat and energy. Eur J Clin Nutr 1990 Aug;44(8):559-66.
12. Matzen, L., et al. Different short-term effect of protein and carbohydrate intake on TSH, growth hormone (GH), insulin, C-peptide, and glucagon in humans. Scand J Clin Lab Invest. 1990 Nov;50(7):801-5.
13. Miles, C. The metabolizable energy of diets differing in dietary fat and fiber measured in humans. J Nutr 1992 Feb;122(2):306-11.
14. Plat, L., et al. Metabolic Effects of Short-Term Elevations of Plasma Cortisol Are More Pronounced in the Evening Than in the Morning. Journal of Clinical Endocrinology & Metabolism. 1997; Vol. 84, No. 9 3082-3092
15. Rampersaud, G., et al. Breakfast habits, nutritional status, body weight, and academic performance in children and adolescents. J Am Diet Assoc. 2005 May;105(5):743-60; quiz 761-2.
16. Reilly, T. and Garret, R. Investigation of diurnal variation in sustained exercise performance. Ergonomics. 1998 Aug;41(8):1085-94.
17. Robertson, M., et al. Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism. Am J Clin Nutr. 2002 Mar;75(3):505-10.
18. Rosmond, R. Role of stress in the pathogenesis of the metabolic syndrome. Psychoneuroendocrinology. 2005 Jan;30(1):1-10.
19. Spaulding, S., et al. Effect of caloric restriction and dietary composition of serum T3 and reverse T3 in man. J Clin Endocrinol Metab. 1976 Jan;42(1):197-200.
20. Stubbs, R. Breakfasts high in protein, fat or carbohydrate: effect on within-day appetite and energy balance. Eur J Clin Nutr 1996 Jul;50(7):409-17.
21. Van Cauter, E., et al. Roles of Circadian Rhythmicity and Sleep in Human Glucose Regulation. Endocrine Reviews. 1997; 18 (5): 716-738.
22. Vernikos-Daneliss, J., et al. Changes in glucose, insulin, and growth hormone levels associated with bedrest. Aviat Space Environ Med. 1976 Jun;47(6):583-7.
23. Vessby, B. Dietary fat and insulin action in humans. Br J Nutr. 2000 Mar;83 Suppl 1:S91-6.