Although carbohydrates constitute the primary and preferred body fuel during most forms of exercise, recent studies show that the timing of your carbohydrate intake can have dramatic and rapid effects in terms of reducing bodyfat. This is particularly true if you're insulin
insensitive, as are many people who carry excess fat on their bodies. Ostensibly, consuming a meal before training provides both physical and psychological benefits. The physical benefits depend on meal timing; if you eat an hour or more before training, the meal will help maintain
a more stable blood j glucose level. This, in turn, not only provides energy but also helps psychologically, since the brain is extremely glucose sensitive.
From a fat-burning standpoint, however, eating before training may not be effective and may hinder the fat-mobilizing process. Some of the mechanisms behind this effect are discussed in a new study published in a i 1995 issue of the American Journal of Physiology. The article notes
that eating before training stimulates insulin flow, i especially if the meal stops.
The study examined the effects of eating before exercise vs. exercising before eating, with subjects having a meal either before training or within 30 minutes after the workout. The results showed that not eating before training increased glycogen breakdown 1.4-fold more than
eating before a workout, and glycogen synthesis increased by 1.9-fold if food was consumed after the workout, not before. Training after an overnight fast also produced a 65 percent energy expenditure derived from carbs during training, while 35 percent of the energy came from fat
stores. The increased fat use after fasting may come from decreased insulin secretion.
The researchers conducting the study suggest that fasting before exercise may be particularly beneficial to obese people, who are already insulin resistant. The in crease glycogen breakdown that occurs in the absence of a preworkout meal will stimulate increased muscle glycogen
synthesis, since there's a feedback mechanism in muscle that relays low glycogen messages and also turns on the muscle enzyme that controls glycogen synthesis. The study confirms a practice that some bodybuilders favor: training in the morning before eating. Bodybuilders do this
to maximize fat burning, since liver glycogen stores are relatively low at that time and the body will tap into fat stores faster than if you eat.
This method may not be appropriate for out-of-shape N obese people, however, because they lack the required I amount of oxidative enzymes is rich in carbohydrates. When insulin levels are high, fat burning needed to fully use fat during exercise. Instead, their bodies will just
tap into glycogen stores, which will improve insulin sensitivity but lower blood glucose. This, in turn, may cause extreme hunger, making it much harder to diet.
Sweet and Low
According to a new study published in the International Journal of Obesity, the latest fat burner may be none other than saccharin. Yes, that stuff in the pink envelopes that fell by the wayside with the advent of another artificial sweetener, aspartame. Most artificial sweeteners
remain mired in controversy. Depending on who you talk to, they're either the greatest boon to dieting or potentially lethal chemicals associated with everything from cancer to convulsions. The health reports on sodium saccharin have been equivocal. When a report surfaced a few
years ago implicating saccharin as a possible carcinogen, the Food and Drug Administration moved to have it removed from the market, but the resulting uproar from both dieters and diabetics effectively curtailed the FDA'S efforts.
Saccharin is indeed a tumor promoter, albeit a very weak one. It is not, however, a mutagen; that is, it doesn't in itself cause cancer, but it may promote preexisting tumors although you'd have to consume about a truckload a day. Let's put it this way: Anaholic steroids and growth
hormone are far more effective tumor promoters than sacchatin consumed in normal amounts.
The new study on saccharin's effect on fat shows that it may promote lipolysis, or fat breakdown, by stimulating an enzyme called adenylyl cyclase, which plays a pivotal role in that process. The study involved rats that were fed diets containing I to 5 percent sodium saccharin
dissolved in their drinking water for 14 days. Other rats were not given the saccharin or were given aspartame, and the aspartame rats showed no increased fat-mobilizing effects. The researchers concluded by noting that although we cannot extrapolate results obtained in rats to
humans, it would be interesting to establish whether sodium saccharin used in beverages and foods has a stimulatory effect on human fat cell lipolysis.
How Long Does Creatine Last?
Creatine monohydrate is, of course, a hot supplement these days. Even those vehemently opposed to food supplements grudgingly admit that creatine hardly falls into the category of fraud, especially considering the breadth of continuing research on it. A new creatine study that
appeared in a 1995 issue of the journal Acta Physiologica Scandinavia confirms a finding about creatine noted in earlier studies and adds a new wrinkle concerning the length of time muscles remain loaded with the substance. The study confirmed a finding concerning creatine's
effects on aerobic exercise; in short, there aren't any. Any advantages offered by creatine supplementation occur only in short, high-intensity exercise, of which bodybuilding is typical. The new study looked at what happens when subjects use a loading program of creatine consisting
of 25 to 30 grams a day for five to six days, then cycle for 60 seconds in successive bouts.
Since the creatine energy system is only involved in the first 30 seconds of exercise, a high-intensity bout consisting of several sets of cycling for 60 seconds a shot wouldn't be expected to show beneficial effects even after a creatineloading program. The newer finding of this
study involved the length of time muscles stay saturated with creatine after getting off the supplement. While older studies showed that muscles appeared to stay creatine-loaded for months, this new study found that muscle tissue creatine returned to baseline levels after the
subjects had not taken creatine for 28 days.