Fasting more effective than low calorie diets?

[Guest guest]

By Alison McCook

NEW YORK (Reuters Health) - New findings in mice suggest that skipping the

occasional meal may be good for your health.

A report released Monday found that a diet in which mice ate only every

other day appeared to protect them more from diabetes and the

memory-robbing Alzheimer's disease (news - web sites) than either a

low-calorie diet or eating as much food as they wanted every day.

" The mice are better off on a diet where they eat fewer meals ... than when

they have continuous access to food, " even if that food is part of a

reduced-calorie diet, study author Dr. Mark P. Mattson of the National

Institute on Aging in Baltimore, land told Reuters Health.

The findings are published in the early edition of the Proceedings of the

National Academy of Sciences (news - web sites).

Although the research was conducted in another species, Mattson said the

findings appear to suggest that, for healthy adult humans, forgoing a meal

now and then may not be such a bad idea, " and it may be beneficial. "

" It may be okay to skip breakfast, for example, " he said.

However, he cautioned against eating nothing for an entire day. " I would

definitely not suggest people do exactly what we did in the mouse study, "

Mattson said.

The mice were forced to fast for a day and then given free reign to gorge

on food the next. Consequently, those who fasted ate as many calories as

did mice given as much food as they wanted every day, the researcher

explained. A third group of mice ate every day, but consumed 40 percent

fewer calories than the other rodents.

After the mice followed the diet for five months, the researchers gave them

a neurotoxin that selectively damages nerve cells important for learning

and memory, a pattern typically seen in Alzheimer's disease.

The researchers found that the toxin damaged fewer nerve cells in the

brains of mice who fasted than in those who either ate freely or followed

the low-cal diet.

Furthermore, blood tests revealed that mice who fasted had lower insulin

levels than those who followed the other diets, an indication they also had

a reduced risk of developing diabetes.

Past studies have suggested that substantially cutting calories increases

life span and reduces the risk of age-related diseases. The fact that

occasional fasting appeared to protect against Alzheimer's and diabetes

slightly better than a low-calorie diet suggests that people can ward off

the effects of aging without starving themselves, Mattson noted.

The current findings appear to contradict the adage that humans and other

animals should eat regularly throughout the day, he added, and suggests

that researchers should take another look at whether that adage is true.

" There needs to be more studies done in humans, because it's very unclear

whether it's important or not to eat three meals a day, " Mattson said.

Looking back over human history, it makes sense that skipping the

occasional meal may serve our bodies well, the researcher explained. Early

humans did not have the luxury of constant access to food, he said, and

many often ate one meal per day or endured several days of fasting before

they found more food.

The humans that survived long enough to reproduce were the ones who thrived

in this environment, he noted, and our modern bodies may not be so different.

By the end of the study, fasting mice weighed more than those given the

low-calorie diet, and slightly less than mice allowed to eat freely,

Mattson said.

Mattson explained that eating fewer meals may protect nerve cells by

placing them under mild stress, which helps them become better at

responding to more stress, such as the neurotoxin.

Diabetes stems from problems in glucose metabolism, and fasting may help

mice avoid diabetes by cutting back on when they receive glucose (in the

form of food), causing their cells to become better at metabolizing it when

the glucose reappears, Mattson noted.

SOURCE: Proceedings of the National Academy of Sciences

2003;10.1073/pnas.1035720100.

[Guest guest]

Hi Kyber:

Thanks for that interesting post. I found your commentary a bit too

cryptic to be sure I got the message! For anyone who didn't get to

read the PubMed abstract, here it is:

" Long-term dietary restriction programs which retard aging processes

in rodents usually involve meal eating rather than the nibbling

pattern of food intake of ad libitum fed rodents. Thus, the

possibility arises that the antiaging action may at least in part

result from an altered temporal pattern of food intake. This

possibility was investigated using male F344 rats maintained on the

following dietary regimens: Group A rats fed ad libitum; Group B rats

fed 60% the ad libitum intake in a single meal at 1500 h; Group B-2

rats fed 60% of the ad libitum intake in two meals (0700 h and 1500

h). The diurnal pattern of plasma corticosterone concentration

differed among the groups as did that of the plasma glucose

concentration. The median length of life and age of tenth percentile

survivors were similar for Group B and B-2 rats and much greater than

those for Group A rats. Both modes of dietary restriction influenced

age-associated disease processes in a similar fashion. Thus, although

the temporal pattern of food intake influenced circadian rhythms of

food-restricted rats, it did not significantly affect the antiaging

action.

PMID: 7814779 [PubMed - indexed for MEDLINE] "

It was published in 1995.

Rodney.

> > It's been done before, though, if I'm catching your meaning. See

> > http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

> > cmd=Retrieve & db=PubMed & list_uids=7814779 & dopt=Abstract

> >

> > Cheers,

> > Anson

>

> And the punchline from the abstract...

> " Thus, although the temporal pattern of food intake influenced

circadian

> rhythms of food-restricted rats, it did not significantly affect the

> antiaging action. "

> Curious, then.

> CR and one meal a day, no different from CD and two meals a day.

> Yet supposedly no CR and one meal every day (or less), better.

> So confusing.