investigating which ones are scientifically sound, and actually work.

From the outside it seems like a simple equation: your weight is determined by the balance between

the calories you take in, and the calories you burn. By changing what you eat or your

activity level, you can tip this equation towards weight gain or loss. Which brings

us to our first category of diets:

Calorie Restriction. Companies like Weight Watchers claim you can eat whatever you want,

as long as you stay below a prescribed number of daily calories. Getting all your calories

from junk food is technically allowed, but from a health perspective, it’s important

to think of the nutritional value of the foods too. If you don’t, you risk heart problems,

nutrient deficiencies and chronic health issues.

Calorie Restriction with Optimal Nutrition or CRON diets, generally reduce their caloric

intake by 20% while still meeting the daily nutritional requirements. For example, instead

of having a whole apple, a CRON dieter will just have the apple skin, which contains most

of the nutrients.

If used properly (and not excessively), calorie restriction can be a safe and effective tool

for weight loss.

Next up is Carb Restriction. Many diets like the South Beach, Atkins, or Zone Diet suggest

that carbs are the enemy of the fit body you’ve always dreamed of.

The ideology claims that when more carbs are taken in than burned off, the liver converts

them into fats. But for most healthy, reasonably active people, carbs are broken down to glucose

and transported to the cells for energy. Very little is actually turned into fat.

In response to excessive glucose, the body uses insulin to turn it into glycogen, which

is stored in the liver and muscles. This glycogen may later be broken down in times of low glucose,

to refuel the body.

But the type of carbs you eat do matter - those from simple sugars like honey, fruit or sugar

are more readily turned into triglycerides or fat than complex carbs like whole grains

and veggies. If you consistently eat way more than necessary, and most calories are simple

carbs, then these will be converted to fat.

Low carb diets often have extreme restriction at first; no starches like bread or pasta,

and no sugars including from fruits or even alcohol. This can lead to some intense side

effects, including constipation, dry mouth, bad breath, fatigue, dizziness and nausea.

In studies, carb restriction dieters tend to lose weight faster, initially, compared

to those simply using calorie restriction, but this is likely due to water loss, which

returns in later phases when you’re encouraged to eat normally again.

On top of this, the Atkins diet, for example, promotes caloric intake from high-fat and

high-protein sources, which means meats, cheeses, cream, butter and...losing weight? Sounds

pretty good right? But many doctors show concern over the high intake of saturated fat - that

may lead to more ‘bad’ cholesterol and therefore an increased risk of heart disease.

Some claim these kinds of diets are dangerous and unhealthy, given that they promote the

limitation of foods like carrots, sweet potatoes, or apples, that provide the body with important

micronutrients and vitamins. Instead, people require supplements, which the body is not

able to absorb as effectively as vitamins, minerals and micronutrients in whole foods.

Then there are High Protein Diets. The main principle is that protein rich foods are not

as easily broken down by the body and take more energy to digest than carb-rich food.

This means you won’t feel hungry again as quickly, and you’re more likely to run a

caloric deficit than if you ate the same number of calories from carbs.

The Paleo Diet, for example, suggests that 10,000 years ago agriculture was introduced,

and the human diet changed from hunter-gathers eating primarily meat, wild fruits, veggies

and nuts, to diets containing more grains. And as a result, some believe the human body

isn’t designed to digest these processed foods like grains, dairy, and breads. Some

also believe that grains lead to inflammation related health problems, but this is largely

untrue except in the case of people with celiac disease.

But because of it’s straightforward guidelines, many find it easy to follow, and it does promote

more nutrient absorption. However, as paleo cuts out all grains and legumes, we lose an

important source of dietary fibre necessary to keep our bowels running smoothly. Not to

mention the high protein leads to nitrogen production meaning stinky farts! Add to that

constipation which allows your digested material to sit longer in the large intestine and continuing

to decompose and...yup. Smelly farts.

Now there is another class of diets we might call the “Just Stop Eating” Diets. Those

looking to ‘get slim quick’ might be tempted to only eat cabbage soup for 7 days, or do

the ‘Master Cleanse Diet’ which only allows salt water in the morning and a concoction

of water, maple syrup, lemon and cayenne pepper through the day, and a laxative tea at night

- but these diets are exceptionally unhealthy. Not only is most of your weight loss from

water weight, but there are many side effects such as dizziness, fatigue, dehydration and

nausea.

The Master Cleanse can ever lead to a white tongue, which some claim is the toxins leaving

your body, but it’s actually due to swelling and a yeast infection of the mouth. And after

going through all that, you’re likely to gain any weight lost after stopping.

Then of course there are straight up crazy diets. Like eating cotton balls dipped in

soup or juice so that you feel full, which of course provides hardly any nutritional

content and can cause intestinal blockages which require surgical intervention.

Or how about the sleeping beauty diet where you just...sleep? You can’t eat if you’re

always asleep! The truth is most diets focusing on quick, dramatic results also have a ‘yo-yo’

effect, where you lose initial weight but slow down your metabolic rate, so your body

starts burning less calories. And when you start eating again...there’s all the weight

back, and often more!

After following contestants from the show ‘The Biggest Loser’ for 6 years - some

of which who had lost hundreds of pounds in 7 months - scientists noticed something interesting.

Not only did most of the participants in the study regain their weight, but their metabolic

rates changed. One man in particular now burns 800 fewer calories a day than would be expected

for a man his size! This is 6 years after leaving the show, showing how extreme measures

to lose weight - while they may be successful at the time - have long lasting impacts on

your metabolism, making it harder to keep off weight in the future.

The hard truth is, that even using many of the principled diets, about 97% of people

regain everything lost and sometimes more within 3 years. If you want to lose weight,

finding a diet that works for you and keeps you motivated, with small incremental changes

is important. Of course, a number on a scale doesn’t measure how healthy a person is,

though many struggle with this perception. If food and weight preoccupations are a problem

for you or someone you know, check out the description of this video for links with more

information.