Less inflammation
‘High levels of body fat are associated
with increases in inflammatory markers,’ says H&F’s nutrition expert Amanda
Hamilton, in her new book Eat Slim Fast (Duncan Baird, $13.5; out 9 May).
Inflammation in the body can present itself in a number of ways, from eczema,
arthritis and asthma to Alzheimer’s, osteoporosis, Parkinson’s disease and
cancer. Studies of varied fasting diets show inflammatory markers reduce during
periods of fasting, she says. In his own study Dr. James Johnson, author of The
Alternate-Day Diet (Michael Joseph, $22.5), found inflammation reduced faster
with intermittent fasting compared to any other weight loss study. Levels of
uric acid increased, which is the body’s antioxidant response, while the
inflammatory hormone lepton decreased.
‘High
levels of body fat are associated with increases in inflammatory markers,’
Johnson studied the effect of fasting on
asthma. Within three weeks of alternate-day fasting, participants felt more
energized, and by the end of the eight-week study, their peak expiratory flow
(the amount of air someone can blow out in a single breath) had significantly
increased.
Heal their heart
Cardiovascular disease has a number of
contributing factors, including obesity, high blood pressure and high
cholesterol. Most of the research shows that fasting can quickly reduce high
levels of ‘bad’ LDL cholesterol and fatty triglycerides in the blood, says
Hamilton.
For example, a study in the Journal of
Nutrition & Metabolism in 2012, suggests intermittent fasting with calorie
restriction on non-fasting days, can lower LDL cholesterol by almost 20 per
cent and triglyceride levels by 17 per cent in 10 weeks. And Johnson found that
levels of nitro tyrosine – high levels of which are associated with a pending
heart attack – dropped by 90 per cent when people fasted on alternate days for
an eight-week period, with most changes occurring in the first 30 days. The
decrease was maintained even when participants indulged on their non-fasting
days.
Cardiovascular
disease has a number of contributing factors, including obesity, high blood
pressure and high cholesterol.
A nimble brain
While fasting might leave you hungry and
affect your concentration, there’s evidence that it can boost your brain cells.
The link between obesity and impaired cognitive function has already been
widely researched, but advocates say intermittent fasting could prevent the
onset of memory loss and age-related diseases such as Alzheimer’s. Researchers
from the National Institute on Aging discovered that by not eating anything for
one or two days a week, the risk of lab rats developing dementia was greatly
reduced and their lifespan was increased by 40 per cent. Professor Mark
Mattson, the study’s lead scientist, says the shock of fasting encourages the
brain to grow new cells, making memory and cognition sharper. ‘There’s an
increase in adaptive stress responses when people intermittently fast that is
good for maintaining the brain,’ he says. While fasting is not recommended for
the elderly, it may be beneficial if you have a history of Alzheimer’s or
dementia in your family.
It battles diabetes
Increased type 2 diabetes is one of the
most worrying consequences of the obesity epidemic. Diabetes UK estimates that
by 2025, 5m people in the UK will have diabetes. While it’s not advised that
people who have type 1 diabetes fast (it would be too hard to maintain blood
sugar control), there’s evidence intermittent fasting can reduce blood glucose
levels, which could improve insulin sensitivity for people at risk of type 2
diabetes. Harvie’s study found insulin levels dropped by a further 40 per cent
when participants followed the two-day diet, compared to a standard
calorie-restricted diet. If your fasting blood glucose levels are above
5.8mmol/l you could be at risk of pre-diabetes. Ask your GP for a free blood
sugar test.
Harvie’s
study found insulin levels dropped by a further 40 per cent when participants
followed the two-day diet, compared to a standard calorie-restricted diet.
It may fight cancers
Fasting as a method of cancer prevention
and assisting cancer treatment is an exciting area of research, says Hamilton.
Human studies are ethically tricky, so most of the research has been done with
mice. For example, a French study testing mice genetically predisposed to
develop cancer, found that alternate-day fasting offered protection against the
disease. After four months, 33 per cent of the mice who had not been fasting
developed cancer, whereas none of the fasting mice did.
Another lab study by the University of
Southern California found fasting protected healthy cells but not cancer cells
against chemotherapy, which could make treatment more effective. Clinical
trials with humans would be needed to confirm this, but high levels of the
hormone IGF-1 in the blood, which studies show rise when you overeat, are
linked to both prostate cancer and post-menopausal breast cancer, according to
Cancer Research UK.
