Exercising before breakfast is better for fat loss: NYT

[iam8bit]

Q: What is the best time of day to exercise, if my goal is weight loss?

A: You might try setting your wake-up alarm earlier and exercising before breakfast. There is some evidence that working out on a completely empty stomach — or, as scientists call this woozy, wee-hours condition, “in a fasted state” — prompts the body to burn more fat and potentially stave off weight gain, compared to exercising at other times.

In a groundbreaking 2010 study, researchers in Belgium persuaded young, healthy men to stuff themselves for six weeks with a diet consisting of 30 percent more calories and 50 percent more fat than the men had been eating. Some of the volunteers remained sedentary while gorging. Others began a strenuous, midmorning exercise routine after they had had breakfast. The third group followed the same workout regimen, but before they had eaten anything.

At the end of the six weeks, the sedentary group predictably was supersized and unhealthy, having gained about six pounds each. They had also developed insulin resistance and larded their muscles with new fat cells. The men who exercised after breakfast had also packed on pounds, about three pounds each, and developed insulin problems. But the men who had exercised first thing in the morning, before eating anything, had gained almost no weight and retained healthy insulin levels. Their bodies were also burning more fat throughout the day than were the other men.

Of course, the early-morning exercise prevented weight gain, which is not the same thing as inducing weight loss. But the results are encouraging for those who hope to shave off a few pounds, said Peter Hespel, a professor in the Research Center for Exercise and Health at Catholic University Leuven in Belgium and the study author.

“The optimal strategy to prevent increases in body weight is obviously to combine a healthy, well-balanced diet with a physically active lifestyle,” he said. But if you are cheating on the healthy and well-balanced diet part, “we demonstrated,” he said, “that early-morning exercise in the fasted state is more potent than an identical amount of exercise in the fed state” for maintaining healthy waistlines.

Source here.

Thoughts?

[AncientYouth]

I always train early am and don't eat until about 1pm


I don't think it makes any difference at all.

how much you eat compared to how much you burn overall is key

[n0useforaname]

Maybe there is some science I'm not aware of, but in all the reading I've done, and all the trial and error... Whether I was fasted, full stomach, did cardio, no cardio, etc... fat loss came the same as long as I adjusted my calorie intake properly. I'd say if it does matter.. it's very, very, very, very, minimal.. like not worth it minimal.

[AndYUKnowThis]

Not possible for me. I'd die

[SPEEED]

That's how I train (both weights and cardio), so I like it

[Znik]

Just skimmed fast through it, seems kinda interesting. Especially that the fasted exercise group had a bigger glycogen increase than the fed, but the fasted has higher bw on average than the CHO so it might be nothing.

Major flaws are lack of better methods for measuring bodyfat, calipers are ... usually not very accurate. And of course the low number of test subjects. Nor is the weight gain difference that special, water retention could easily affect it. 0.8kg vs 1.4kg , like 1lb difference after 6 weeks.

So the things that I did found interesting is the bigger increase in glycogen and :

Energy balance in muscle cells during contractions is more easily maintained when carbohydrate availability is abundant, than when carbohydrate supply is limited (Spencer et al. 1991), which may stimulate AMPK signalling. Accordingly, we (De Bock et al. 2005) and others (Akerstrom et al. 2006) have previously demonstrated that an acute exercise bout in the fasted state increased muscle AMPK activity more than an identical exercise bout in conjunction with ample carbohydrate intake. Although this was not found in another study, fasted exercise still resulted in a higher AMP/ATP ratio in muscle (Lee-Young et al. 2006). Based on the above observations during acute exercise, it is tempting to speculate that exercise training in F might increase the baseline level of AMPK activity to facilitate long-term energy homeostasis in muscle cells. Consistent with this assumption, we found training in F, but not in CHO, to increase the degree of AMPKα phosphorylation

and

In this study we administered a hyper-caloric HFD to healthy subjects and demonstrated for the first time that early morning exercise in the fasted state is more potent than an identical amount of exercise in the fed state to improve whole-body glucose tolerance, as well as to induce beneficial adaptations in muscle cells that eventually may contribute to improved peripheral insulin sensitivity.

[dmacdonal9]

In this study we administered a hyper-caloric HFD to healthy subjects and demonstrated for the first time that early morning exercise in the fasted state is more potent than an identical amount of exercise in the fed state to improve whole-body glucose tolerance, as well as to induce beneficial adaptations in muscle cells that eventually may contribute to improved peripheral insulin sensitivity.

I think that's the key thing. Untrained obese people can get some pretty impressive improvements in insulin sensitivity by doing any number of things, and they can often see some body composition changes as a result. Trained people usually have pretty good insulin sensitivity though, and so the incremental change is smaller, perhaps non-existent.

[iam8bit]

After visiting this forums for a couple of years now, my general understanding was that meal timing mattered very little, but from this study it seems the impact is pretty significant. Of course, you'd need a number of studies like this to conclude anything, but I thought it was interesting.

Personally, I do cardio just after waking up and before breakfast because I find it easier and more convenient. I prefer to walk/jog on an empty stomach than after a meal, when I may feel heavy and bloated.

I think that's the key thing. Untrained obese people can get some pretty impressive improvements in insulin sensitivity by doing any number of things, and they can often see some body composition changes as a result. Trained people usually have pretty good insulin sensitivity though, and so the incremental change is smaller, perhaps non-existent.

Interesting. So maybe this method is better for people just starting out?

[dmacdonal9]

Interesting. So maybe this method is better for people just starting out?

Well, maybe, but only in the sense that pretty much anything and everything is better for people just starting out. The improvement you get from your first 12 weeks of lifting is an order of magnitude greater than the improvement you'll see at the two year plus 12 week point for example.

Take a couch potato and have him walk 30 minutes a day. All of his health markers across the board will improve dramatically. Take an athlete and have him do that, and it's not going to move the needle.

[karlton3]

I think the idea is loosely tied to the notion that insulin limits HSL (slowing fat lipolysis) and catecholamInes (slowing fatty acid mobilization) and that insulin levels are lowest when fasted.

[Znik]

Some more on the subject of fasted morning cardio:

. Both groups showed a significant loss of weight (P = 0.0005) and fat mass (P = 0.02) from baseline, but no significant between-group differences were noted in any outcome measure. These findings indicate that body composition changes associated with aerobic exercise in conjunction with a hypocaloric diet are similar regardless whether or not an individual is fasted prior to training.

http://www.jissn.com/content/11/1/54/abstract

Author on the study:

A single study is simply a piece in an evidentiary puzzle and can never considered the final word on a topic. What I do think is clear from our study, however, is that if there are any benefits from fasted cardio (still highly equivocal), they would be minor at best. So the best advice for those who are simply looking to get lean is to focus on total energy and macronutrient balance; whether you perform cardio fasted or fed should depend entirely on preference.

On the other hand, it remains possible that a small benefit could be seen by performing fasted cardio. If such an effect does exist, it would seem to be only meaningful to someone who is competing in a bodybuilding or physique competition, where minute differences in fat mass could make the difference between winning or losing a competition. I will point out, however, that it also is conceivable fasted cardio could have a negative effect in this regard. A recent study by Paoli et al showed that lipid utilization over 24 hours was actually higher when eating prior to cardio as opposed to remaining fasted. Thus, the best advice here would be to experiment and try to objectively determine what works best for you as an individual.

The lower lipid utilization study:

In both cases, the same total amount and quality of food was assumed in the 24 hr after the training session. The breakfast, per se, increased both VO2 and RER significantly (4.21 vs. 3.74 and 0.96 vs. 0.84, respectively). Twelve hours after the training session, VO2 was still higher in the FED test, whereas RER was significantly lower in the FED test, indicating greater lipid utilization. The difference was still significant 24 hr after exercise. The authors conclude that when moderate endurance exercise is done to lose body fat, fasting before exercise does not enhance lipid utilization; rather, physical activity after a light meal is advisable.

http://www.ncbi.nlm.nih.gov/pubmed/21411835

[Rich1143]

Working out fasted means your insulin levels are low. You are burning more fat. Working out in a fed state means you are burning calories from your stomach more and not as much from your actual body. I find fasted workouts to be great. Your muscle isn't gonna wither away like many bros would have you believe.