Tag Archive: weight loss

How do low carbohydrate diets work?

Diets low in carbohydrates, or “low carb diets”, have been making their way back into the mainstream due to special recognition of Keto, Atkins and Paleolithic diet lifestyles. Like all “diets” (by “diet” I do not mean “what I eat every day,” but rather “what I’m doing to lose weight now”) they are not recommended for life. Why? Science 🙂

What is a carbohydrate?

A carbohydrate is a molecule that gives the body energy. Carbohydrates have many different functions, but for the argument of this article: carbohydrates derived from food give our body the energy it needs to function (see: Krebs Cycle). They are broken down into glucose, ketones, etc. for use by the entire body. The brain and neurons can only use glucose and ketones (that can pass the blood brain barrier) from carbohydrates for energy.

How does this apply to my diet?

When a carbohydrate is broken down it is used for energy. The most common form of this is glucose in humans. If your body needs energy, it’s more likely to use the carbohydrates/glucose circulating in your blood first for energy. Secondarily, it moves to your liver to extract stored glucose. Muscles can also access stored glucose in muscle cells. Next it removes stored glucose from fat cells. Lastly, it will enter a state of gluconeogenesis, where it creates glucose from non-carbohydrate sources. This is why carbs give great short term energy. If they’re available and the body needs energy they’ll use them preferentially. Excess carbohydrates that are not used stimulate insulin, which takes that glucose and puts it places in your body, such as your liver and fat cells.

So why are carbs important if we can just get energy from fat or our livers?

Your brain can only use glucose for energy. If your body doesn’t have glucose regularly circulating it has to get it from somewhere. First, it will dip into whatever is stored. Glycogen is the stored form of glucose. Remember how I said extra glucose gets stored? It’s stored as glycogen. If your body needs energy and there’s none there, it opens the cabinets and grabs some glycogen. The first place it gets this from is the liver. Some glycogen is also stored in your muscles so your muscles can have immediate access to it if needed – but ONLY to your muscles.

What happens when you run out of glycogen?

Ever heard of runners “hitting a wall” around mile 20? They’ve used up all of their glycogen. Symptoms include fatigue to the point of almost being unable to move. They have to counteract this by consuming different types of carbohydrates before and during their races.

So now we’re out of glycogen and glucose…what happens?

Your body has to make glucose from somewhere, so it makes it from non-carbohydrate carbon substrates. This creates ketone bodies that must be used for energy instead. Ketone bodies are made from fat during lipolysis, or “fat cutting.” However, the brain cannot use this for energy because ketone bodies cannot cross the blood-brain barrier to feed the brain. Very few ketone bodies do pass and can be used, but not at nearly the high volume of glucose.

What does this has to do with low carb diets?

The idea is that low carb diets decrease your levels of insulin. Since insulin drives glucose into storage cells, you store less fat. Since you have less carbohydrates, when your body needs energy it goes to glycogen in your liver and muscle. When that’s exhausted it has to start looking for other sources of energy. This leads to ketosis, where the body has a high level of ketone bodies. Theoretically, then, if you don’t have carbohydrates (or are low carb) and need energy your body instead burns fat. This is highly debated amongst scientists, as long term studies have shown that after a year on Atkins the average weight loss is 4%.

Is ketosis bad?

This is the big debate. What about cultures that don’t consume a lot of starches, or cultures that are much more active than ours? They spend more time in ketosis than we do. The argument can come from a standpoint of “what is normal?” Some studies have shown that periodic ketosis is normal and may actually have surprising benefits. Others have shown that ketosis predisposes you to heart disease (in this case, high protein diets), liver damage, and other health problems.

What about ketoacidosis? Isn’t that what diabetics get?

Yes. If you have a high level of ketone bodies and your body cannot get rid of them, the blood becomes acidic. This can be fatal. Healthy people with a working pancreas should not have to worry about this – your pancreas secretes enough insulin to prevent this high of a build up. Another concern arises from alcoholics, who dehydrate themselves so much they block the first steps of gluconeogenesis, and then get ketoacidosis. This is not a concern amongst normal, healthy individuals.

So is low-carb good or bad? Effective or not effective?

Calories are king, so avoiding carbohydrates without counting calories will do nothing for your weight loss and may make you feel weak or easily irritated. As for its effectiveness? Here are some studies…

The Effects of Low-Fat and High-Carb diet on the physiological and biochemical indices in healthy youth with different BMIs (no big difference between the two)

Comparison of the Atkins, Zone, Ornish and LEARN diets for change in weight and related risk factors among overweigh premenopausal women (Atkins group lost 4.7 kg in 12 months, Zone lost 1.6 kg, LEARN 2.6 kg and Ornish 2.2 kg)

BUT

Comparison of the Atkins, Ornish, Weight Watchers and Zone diets for weight loss and heart disease reduction (Each popular diet modestly reduced body weight and several cardiac risk factors. OVERALL DIETARY ADHERENCE RATES WERE LOW. Atkins lost 4.8 kg (21 of 40 participants completed) Zone lost 3.2 kg (26 of 40 completed) 3 kg for Weight watchers (26 out of 40 completed) and 3.3 kg for Ornish (20 of 40 completed) )

On the same vein…

Dietary adherence has been implicated as an important factor in the success of dieting strategies

and

Initial 6-month reduction in weight is the main predictor of both long-term retention and success in weight loss. Special attention is needed for women, current smokers and during holidays. Physical activity is associated with subsequent reduction in energy intake.

July 4, 2012 Fat Loss, Nutrition, , , Read more >

Is BMI and accurate way to assess your health?

I’ve often been heard bemoaning the use of “BMI” (body mass index) to quantify health for people, and I get asked why. After all, doctors use BMI to determine health of children and adults alike. It’s including in scientific studies about obesity and overall health. How bad can it be?

Really, really bad.

First, let’s look at how you calculate your BMI. Find a happy little calculator and input your height and weight (sometimes age and gender) and it will spit out a number. You then compare this number to a pre-set list of other numbers that tell you if you’re underweight, just right, overweight or obese.

The calculator did not take into account: body fat percentage, lung capacity, VO2 max, etc.

You see where I’m going with this? Let me use some great examples.

This website lists people at all heights, genders and weights with their pictures. Browse around. Look at someone your height and weight – do any of them look anything alike? Nope. Do they look like you? Nope. So, if people of the same height and weight look drastically different, how can a calculator using only these two figures determine health?

It can’t.

 At my lowest weight my BMI put me at “healthy,” despite eating every other day or eating 500 calories a day. My highest weight puts me near the overweight category, despite having run a few 5k’s and being able to squat almost twice my body weight. BMI is a horrible indicator of anything – health, weight loss, fitness, life, etc.

July 4, 2012 Fat Loss, Myths, Read more >

When losing weight, what food groups should you avoid?

I get this question a fair amount, so I thought I’d do a lovely post on what foods one should ABSOLUTELY avoid when trying to lose weight. I’m talking about the type of food that can single handedly sabotage your diet, make you pack on the pounds and set back all the progress you’ve made.

Ready for it?

They don’t exist.

There is no one food (peaches, candies, steak, cake) or one type of food (alcohol, dairy, meat) that will cause any sort of setback in your diet.

Why? Because food is not the enemy. Treating food items or food groups as horrible fiends that trick you into craving them with their addictive additives and their easy accessibility gives them way too much power. It’s an item, composed of macro and micro nutrients, with assorted tastes, flavors and sensations. That’s all. Some are enjoyable, some aren’t.

Furthermore, eating fruit or not eating fruit isn’t going to make or break your diet. Weight loss, specifically fat loss, comes down to energy balance. If you put yourself into a deficit (either by diet or by exercise) you will lose fat. If you put yourself into a surplus (either by diet or lack of exercise/activity) you will gain fat (and/or muscle, depending). That’s it. If a food has 200 calories it has 200 calories. Done. There’s no further discussion from a weight loss point. (Before I get 1,000 asks talking about how 200 calories of veggies and 200 calories of cake are not the same, save it. For weight loss they are, for health they’re not. Go away. You’re annoying and redundant and clearly can’t read.)

Let’s set up a scenario. Say that your TDEE (the amount of calories you burn a day as an active human being) is 2,100. Maybe you’re trying to lose weight, so you put yourself at a 300 calorie deficit every day and eat 1,800 calories a day. Awesome. It’s about 5pm and you’ve had your meals for the day but there’s something extra you’re craving – like a piece of cake. You’ve got about 350 calories left for the day and your mom just brought home a delicious cake – Cheesecake. Your favorite. Turns out the calories for the entire piece add up to 400 calories and she wants to split it right down the middle.

But cake! That’s bad food! It’s always listed on that “DO NOT EAT” diet sheet! Guess what – you’ve got plenty of room to eat that cake. And you know what? It’s your favorite. You’ve worked hard. You have the space for it in your meal plan. You’re still hungry and you WANT this cake.

So eat it. Those 200 calories you just ate of cheesecake isn’t going to suddenly morph into 800 calories in your stomach, then grow to 3,500 calories in your intestines and set back all that great progress!

Say you don’t have any extra calories left for the day but you want the cake and you eat it. You’ve eaten 2,000 calories that day. 2,100 calories will keep your weight. 3,500 calories + 2,100 calories will make you gain a pound.

Take this same advice with any food. No, adding milk to your cereal isn’t going to make you gain weight. Adding milk to every item you eat all day, causing you to go over your calorie limit, will. See how that works?

Instead of obsessing over “good food” and “bad food” focus on how food makes you feel. If you really love a type of food, find a way to incorporate it into your diet in a healthy way. Find recipes that make a smaller serving size so you aren’t plagued with an entire cheesecake going bad in your house. Split desserts with your friends, get rid of the “bad food/good food” dilemma. Food is food.

What you shouldn’t focus on is the food, but the feeling. Do you find that chicken makes you feel full longer without putting you into a food coma? Does too much dairy make you gassy and uncomfortable? Do certain carbs make you retain water like crazy? Are you highly reactive to sodium or cholesterol? These cues are SO much more important than the good food/bad food dichotomy because these experiences are highly personal and can’t be generalized like this.

My take? There’s no such thing as bad food, but there is such a thing as too much food. Moderation moderation moderation!

July 4, 2012 Fat Loss, Myths, Nutrition, , Read more >

The Math Behind Weight Loss: Caloric Deficit explained

Losing weight comes down to creating a “caloric deficit.” That is, burning more calories a day than you eat.This takes into account more than your BMR.

BMR = basal metabolic rate. This is how many calories you burn from existing. If you sat around all day and did absolutely NOTHING your body would burn this many calories just to exist.

TDEE = BMR + activity level, or “total daily energy expenditure”. Since the average person doesn’t sit around on the couch and not move at all, this takes into account other things. For example, a sedentary person (who works a desk job and doesn’t exercise) may have a TDEE slightly above their BMR. Someone who is very active (their job is manual labor, or they lift very heavy multiple times a week) may have a TDEE almost twice their BMR.

How do you calculate your BMR or TDEE? Let’s cut the math – here is my favorite calculator. You input your gender, age, weight, body fat % and “activity level” and it will tell you how many calories you need to maintain, lose weight, etc.

So what is a caloric deficit?

Let’s use a real life example. My BMR is 1550 calories a day, my maintenance is 2,100 calories a day. Based on how often I exercise, how I spend my day, etc. I need to eat 2,100 calories to maintain my weight. If I want to lose weight I need to eat less than 2,100 calories a day. What’s important to note about this number, my maintenance number, is that it takes my TDEE into consideration. I don’t subtract the amount of calories I burn from exercise, that’s already taken into consideration. That’s the definition of TDEE – total daily energy expenditure. It’s already taking into account that I exercise as much as I do, or I’m as active as I am at my job.

If one pound = 3,500 calories, to lose one pound a week I need to have a deficit of 3,500 calories that week. Divided over 7 days, that’s a 500 calorie deficit a day. That means eating 1,600 calories a day for me. It’s also important to remember that your body takes an average. 24 hours is a human invention, as long as you have -3,500 calories a week it doesn’t matter what your day to day intake is. It doesn’t matter if these calories are eaten at 5pm, 6am or 12am.

What is NOT a caloric deficit?

When I was sick I used to think that a caloric deficit meant my total numbers for the day were a negative. Basically, I would eat 600 calories a day and then exercise off 1,000 calories and think that I was in a 400 calorie deficit. What I didn’t realize is that my body requires a certain amount of calories to exist that’s independent of how many calories I eat a day – that’s my BMR.

The BMR Trap

People who don’t understand what BMR is believe they need to eat less than their BMR. What they’re forgetting is that they do more than sit around all day. Yes, some people live very sedentary lives – they work at a computer desk, only get up to use the bathroom, go home and eat dinner in front of the TV. These people may need to eat at their BMR because they don’t move enough to create a TDEE much higher than their BMR. Others – people who walk from class to class, go to the gym a few times a week, have a job where they’re on their feet all day at a restaurant or as a nurse – these people have a TDEE higher than their BMR. If they eat at their BMR they will find themselves energy deprived, sluggish, and fall into the trap of binging to compensate for their low energy.

July 4, 2012 Fat Loss, Read more >

Where does fat go when you lose it?

What is fat?

Fat is extra energy that we store on our bodies. Any time you eat more than your body burns, that excess energy is converted into a storage form and placed various places in your body. The most problematic of these aesthetically (and health wise) is in fat cells, which translate to the padding you carry on your body. Some body fat is healthy and necessary – women require a certain amount in order to produce hormones necessary to maintain their period and become pregnant. Too much fat can be detrimental to our health.

Fat cells

Fat cells are located throughout our body and increase or decrease in size. The average human has 10 billion to 30 billion fat cells located around their body. An obese person can have up to 100 billion. Usually, fatty acids are stored inside these fat cells, making them increase in size. This tends to be genetic – certain people gain and lose fat in certain areas preferentially over others. It’s possible for your body to increase the number of fat cells on their body when they become obese. However, there is no way to “lose” fat cells. When you lose fat off your body, you’re shrinking the size of the fat cells, not getting rid of them.

How do you get rid of fat cells?

Liposuction is the only way to actually remove the fat cells. Otherwise, they remain deflated throughout your body.

So what happens when you lose fat?

Like I said above, the fat cells shrink. If you create a caloric deficit your body pulls energy from these storage forms of fat and uses that. As it pulls the energy out of the fat cells they shrink. That fat is used for energy, and the byproducts are excreted in your urine or feces.

Can the fat cells increase in size again?

Yes. If you start consuming more energy than your body can burn your fat cells will increase in size as that extra energy is stored in them.

July 4, 2012 Exercise, Fat Loss, , Read more >