Ketogenic diet - Can eating fat help you lose weight?
By Christy Brissette September 26
Fat makes your meals more palatable and helps you feel
full, so itís no wonder the high-fat ketogenic diet is increasing in popularity.
The diet has been trending for the past three years, as ďketoĒ blogs and
cookbooks continue to pop up and build an impressive fan base. This diet has
been used under close supervision by physicians and dietitians since the 1920s
treating epilepsy and has shown promise in
managing brain cancer. But is it useful and
healthy as a strategy for weight loss?
First, the basics: On the
ketogenic diet, at least
70 percent of your daily calories
come from fat.
Five to 10 percent of your
calories come from carbohydrates (20 to 50 grams
The rest, up to 25 percent of your
daily energy, comes from protein.
By contrast, the
healthy diet recommended by the Institute of
The ketogenic dietís low-carb target can be met only by
avoiding grains, dairy products, fruit, and
legumes such as chickpeas
and lentils. Starchy
vegetables such as sweet potatoes and
squash are out, and even amounts of
lower-carb vegetables are limited.
So whatís left to eat? Typically,
eggs cooked in
breakfast; for lunch and dinner,
and plenty of oily
dressing. Sorry folks, no alcohol on
this diet. Even red wine is out.
[To get a flatter belly, start by getting enough sleep]
The ketogenic diet gets its name from a process called
ketosis. Ketosis happens when your body doesnít have enough energy from
glucose (carbohydrates), so it adapts by using
stored fat for energy. The result? Weight loss.
Does the ketogenic diet lead to faster or more sustainable
weight loss than other diets? The research to date suggests that initial weight
loss on the keto diet is impressive but that people arenít able to stick to the
regime for long.
study, for example, compared the impact of
a ketogenic diet (where participants ate less than 20 grams of carbohydrates a
day) to a low-glycemic-index diet (where
participants reduced their caloric intake by 500 a day) on weight loss in 49
obese individuals with Type 2 diabetes. After six months, the group on the keto
diet lost an average of 24.5 pounds, while the low-glycemic-index
group lost 15.2 pounds.
But a recent meta-analysis combining the results of 13
randomized-control trials (1,415 participants) of a year or longer found that
people on a ketogenic diet lost an average of two pounds more after a year and
improved their triglycerides, high-density lipoprotein (HDL) cholesterol and blood pressure compared to those
on a low-fat diet. However, when the researchers looked at studies that followed
participants for two years, they found that HDL
improved more in the keto diet group but that there was no difference in weight
loss between the groups.
While the ketogenic diet is promoted as key to switching
your body into fat-burning mode,
research suggests that fat loss actually
slows down as your body starts to break down your muscle for energy.
Pros of the ketogenic diet
1. You donít need to count calories.
Instead of worrying about calories and portion sizes,
some people find it easier to have a list of foods they can eat as much as
they want of. By limiting the foods you can choose, this diet limits your
caloric intake without you having to think about it too much. You might
start out overdoing the bacon and pork rinds, but that wonít last. (See
2. You wonít be hungry.
Research on the ketogenic diet
suggests that the production of ketone bodies lowers your levels of
ghrelin, a hormone that makes you hungry. Essentially, youíre able to stay
satisfied for longer on this diet.
3. Fast weight loss (at first).
When you limit carbohydrates in your diet,
your body uses the carbohydrate stored in your
muscles and liver (called glycogen). Glycogen is stored with
water, so restricting carbs famously helps you lose weight quickly by
causing you to lose water weight. Although it doesnít make you lose ďrealĒ
weight (i.e. fat) or make you any healthier, this early perceived weight
loss can help motivate people to continue with the diet.
4. There are potential heart health benefits.
Cons of the ketogenic diet
1. Itís boring.
2. There goes your social life.
Socializing while on this diet is a challenge, which
is another trade-off most people arenít willing to make.
Alcohol isnít allowed, and having a bite of
dessert isnít, either. Can you be sure the
salad dressing you order on the side doesnít
have sugar or honey
in it? Iíve had clients tell me after trying this diet that they have
turned down plenty of social gatherings to avoid temptation. That doesnít
seem like a healthy lifestyle change to me.
3. Digestive woes
As with other
diets, getting enough
difficult on the ketogenic diet. The result?
Constipation in the short term and, over time, an increased
risk of colorectal cancer. Any diet
that throws off your digestive health should raise red flags.
4. Risk of nutrient deficiencies.
Because the ketogenic diet cuts out so many foods, it
can be deficient in the nutrients
those foods contain ó calcium, magnesium,
selenium, thiamine, vitamin D and
vitamin C. Before trying it, be sure to consult with a
registered dietitian to ensure that youíre meeting your nutrient needs,
especially if youíre planning to follow this diet for more than a couple
[Donít believe those who say smaller, more frequent
meals will control appetite]
5. There are general safety concerns.
Consider that people who go on the keto diet for
epilepsy are very closely monitored by a medical team, so this isnít a
diet to be taken lightly or to do on your own. Anyone with
health problems should speak to a
physician before trying the ketogenic diet. Donít try it if you have
kidney problems, as it hasnít been
studied in people with impaired kidney function. This diet is not safe for
The bottom line
As researchers have
stated, the benefits of the ketogenic
diet are of
little clinical significance ó that is, any advantages over
other diets are too small to make a difference in your life. Consider how
following such a restrictive diet will affect your quality of life and
enjoyment of food.
People who feel more energized on
lower-carb diets and enjoy eating
fats and oils could
do well on the ketogenic diet. Anyone like me who loves their
fruits, whole grains
and vegetables will struggle to avoid
their favorite foods. Are you willing to give up that piece of dark chocolate
or Greek yogurt with berries?
In the end, the best diet isnít really a diet at all.
Itís a way of eating you can stick to that will boost your overall health ó
and wonít leave you feeling zapped or require you to be antisocial.
Christy Brissette is a dietitian, foodie and president of
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