DrG's Medisense Feature Article
13061-Best_Diets
The
‘Best’ Diet
by Ann Gerhardt
June 2013
Print Version
During
a long conversation about the best way to ensure healthy longevity with
a patient who knows a lot about food, she asked, “So how do I
know what’s right?” I suggested that she
already eats well and she should trust her own judgment.
Lately she has lost that trust and has been guided by books extolling
the virtues of juicing and raw, organic, vegan, fermented or salt-cured
foods.
None of these are inherently bad, but each deserves an informed
approach. We discussed the infections she can get from eating
raw food, the pros and cons of fermented, salt-preserved and organic
food, and the pros and cons of eschewing all animal products for a
vegan approach. I asked her to take pity on her colonic
bacteria, which she needs for optimal health, and feed them the fiber
from fruits and vegetables, instead of juicing it away.
Given the complexity of our discussion, she wanted to know what book
she should read. If you want to learn unadulterated
nutrition, buy a nutrition textbook. But even a text misses
some things and every day research adds to the collective knowledge, so
texts are by their nature out of date as soon as they are
printed.
So what about diet books? Diet books all have a motive
– to make the author money, serve as a platform for
proselytizing, or both. They usually focus on weight loss
rather than general health, and all have a gimmick: Some of
the most colorful include The Drinking Man’s Diet and the
Blood Type diet (we’ve all got one, so who’s not to
buy it?). Gimmicks set the book apart from the others, and a
fair portion of the book is generally devoted to setting forth
scientific ‘proof’ that the gimmick
works. The body of nutrition knowledge is so vast that a diet
book can’t contain it all. Any factual information
is necessarily distilled into a form that fits the premise of the book,
without detracting from pages devoted to food plans and
recipes.
I steered her in the direction of Michael Pollan’s Book, Food
Rules, An Eater’s Manual, in which he decries the
over-intellectualization of food and eating. (See my review
in DrG’sMediSense, March 2012). He has his own
bias, as evidenced in his other books, but Food Rules leaves out his
selective reading of the science (he’s a journalist, not a
scientist) and cuts to the core of how to eat healthfully.
Having said all that, if I haven’t talked you out of a diet
book, here is a review of some of the best and the worst.
Every diet must have one thing: A way to limit calorie
consumption long enough to lose a few pounds. One could hire
people to control your food intake (a la Oprah), compulsively measure
portions to constrain volume (the epitome is Weight Watchers) or
eliminate certain foods or food groups (all the rest). Eat no
fat, no sugar, no white food, only raw food, only food that fits your
blood type, only food that Paleolithic people ate, only food you can
eat while standing on your head and playing the harmonica, etc.
In my opinion (and that of a lot of dietitians) books that ensure good
nutrition and enable healthful weight loss generally recommend
‘prudent’ diet patterns. These include a
variety of whole grains, vegetables, fruits, dairy foods, vegetable
oils and lean protein sources, and usually limit total calories, salt,
alcohol and nutritionally ‘empty’ foods (for
instance, Chee-tos). Unfortunately, the word
“prudent” doesn’t usually sell books to
the American public. Catchy titles do, like the
Anti-Inflammatory Diet, Flat Belly Diet, Abs Diet, and Engine 2
Diet. Each of these has some reasonable advice but inflate
their scientific claims and employ unnecessary gimmicks.
The Mediterranean, Flexitarian, Mayo Clinic, Volumetrics, DASH and
Weight Watchers diets fit the ‘prudent’
description. This is not an exclusive list – Others
may shirk the gimmicks and propose rational advice also.
The Mediterranean diet isn’t so much a made-up diet as it is
a description of the daily dietary habits of people living along the
Mediterranean coast. Though specifics change from region to
region, all include fruits, vegetables, olive oil, fish and some starch
or grain food. Along with physically active lives, this
dietary pattern contributes to health and longevity as well as weight
control.
The Mayo Clinic diet emphasizes low calorie foods with high nutrient
value, such as vegetables and fruits, whole-grain carbohydrates and
lean proteins (beans, fish and low-fat dairy), unsaturated fats and
exercise. There is no calorie counting or food elimination,
and it encourages habits that enable such a plan and discourages habits
that sabotage it.
Flexitarians are “flexible vegetarians,” people who
are mostly vegetarians but indulge in an occasional steak or fried
chicken when the urge hits. The bulk of the diet contains
veggies and fruits, whole grains, dairy and protein from tofu, legumes,
seeds and eggs, all with a kick of flavor from diverse spices.
Recognizing that people basically like to eat large amounts of food,
the Volumetrics approach focuses on filling up on low-calorie, bulky
foods. That means vegetables, fruits, non-fat milk,
broth-based soups, and low-fat, low-sugar versions of food from all the
other food groups. High caloric density foods like crackers,
chips, cookies, candies, nuts, butter, oils and alcohol are only
allowed in small quantities.
The DASH (Dietary Approaches to Stop Hypertension) diet was designed to
lower blood pressure. It includes low-salt foods that are
also high in potassium, calcium and magnesium, all of which combat
hypertension. Low-salt versions of whole grains, vegetables,
fruits, low-fat dairy, lean meat, fish, poultry, nuts, seeds and
legumes fit the bill for DASH. The diet limits fats, sweets
and alcohol and encourages exercise.
Weight Watchers has changed over the years, from weighing and measuring
to the point system to the low fat/high fiber version.
Through it all, the basic diet emphasizes the
‘prudent’ approach to food choices and minimizes
calories from foods bereft of any nutritional value.
Then there are the other diets, with variable redeeming
characteristics. Jenny Craig and Nutrisystem are generally
balanced and very easy to follow, but are expensive and may have too
much salt and not enough fiber, fresh vegetables and fruits.
They are also hard to transition to normal food without reverting to
old eating habits, since the dieter really hasn’t learned how
to eat on his own.
Vegetarianism done right, with a variety of food groups and protein
sources is a fine dietary pattern. Without portion control
and balance, though, it doesn’t guarantee weight
loss. For example, cookies, cakes and potato chips are
vegetarian, and there’s no a priori rule of vegetarianism
that precludes eating them all day. Even healthy food has
calories, and without portion control too many servings can pile on the
pounds.
Extreme vegetarian diets, like the Ornish Diet and
Esselstyn’s Prevent and Reverse Heart Disease, are
nutritionally sound, but go a bit overboard. They are hard to
follow and may restrict fat too much for some people. It is
possible to reverse heart disease with a less extreme diet (still heavy
on plant foods), especially when accompanied by plenty of
exercise.
The Macrobiotic Diet is an almost-vegan diet combined with spirituality
and rules about eating, cooking and lifestyle. To conform to
a goal of balancing yin and yang foods, it even limits some
vegetables. The original Oriental version progressively
restricted foods, culminating in brown rice and water as the ultimate
in yin and yang. It’s a hard diet to follow, and
the severe restrictions make it easy to end up with protein deficiency,
Traditional ethnic diets that include plenty of vegetables, like Asian
and Indian cuisine, are reasonably healthy, but may use too much salt
and don’t limit starches, so the overall balance might be
off, depending on how they are done. In general, though, each
ethnic diet has something good about it, which might be used as part of
a ‘prudent’ plan.
The South Beach, Zone and Atkins Diets unnecessarily restrict starches
and are too hard to continue for very long. A lot of studies
comparing low fat and low carbohydrate diets basically came to the
conclusion that people can lose weight faster with the very low
carbohydrate diets, but over time both types produce similar weight
loss and improved health parameters. Some people (like
diabetics) do well with carbohydrate deprivation and others get killer
headaches and nausea and have switch back to more normal food.
The Raw Food diet isn’t necessarily nutritionally complete
and is hard to follow for very long. Just how does one eat
raw bread or rice? There’s also the very real
concern of infection. One of the reasons we cook is to kill
food’s hitch-hiker organisms before they can cause
infection. Even organic food must be very fresh and washed
extremely carefully, because organic farmers often use manure as
fertilizer.
The Paleo Diet, consisting of wild plants, fish and meats, might sound
good, but foods that Paleolithic man ate might be hard to find these
days. The name is a bit disingenuous, since beef, sauerkraut,
and Baba Ghanoush weren’t staple items for hunter gatherers
of yore. Eliminating cereal grains, legumes, dairy and
potatoes unnecessarily cuts out nutritious foods and can lead to
vitamin and mineral deficiencies. This is really just a cute
name for another low carbohydrate diet.
The Glycemic-Index diet is geared to pre-diabetics, diabetics and
people who carry their weight in a spare tire around their
middle. It is based on the fact that some carbohydrates are
digested into simple sugars and absorbed into the body faster than
others. Some don’t get absorbed at all and are
termed ‘resistant starch.’ Those turned
into lots of sugar quickly are termed high-GI. One could eat
only low-GI foods but not lose weight, depending on their quantity and
the food eaten with them. So the ‘diet’
combines low-GI foods with low fat dairy and protein and limits portion
sizes of everything. It’s not a bad plan, just a
bit complex, especially when one considers that a food’s GI
can be affected by other foods in the meal.
Liquid diets, like Slim-Fast and Medifast, are easy to follow, but are
severely restrictive. These semi-starvation diets cause
ketosis, an elevated level of fat’s breakdown products that
make you lose your appetite. They are nutritionally marginal
and often cause gallbladder attacks and other complications.
When the diet is over, weight rebounds quickly without severe calorie
restriction and excessive exercise.
Which brings us full circle to the
concept of “diet.” Diet is, generically
speaking, what we eat, whether it makes us fat, skinny, healthy or
sick. Any new diet plan only works for as long as it is
followed. Extreme diets are either too hard to follow for
very long or elicit food cravings that sabotage the effort.
The best diet is one that limits portions to those commensurate with
your ideal weight, and includes lots of vegetables and foods consistent
with a ‘prudent’ balance.