Stagnation Mode

Has your fat loss plateaued despite your dedicated efforts?  Do you feel like it gets increasingly difficult to achieve fat loss the harder you work?  Are you afraid that your body has gone into 'starvation mode,' or that you've ruined your metabolism?
Fear not!  Chronic dieting does not permanently damage metabolism, nor does it alter the physics of how your body processes food.  I know, your FitBit says you're burning 2000 some-odd calories and you're down to eating 1000 calories, why no fat loss?  Your body doesn't need an upgrade or a re-boot, your information about fat loss and energy balance does.    

Let's begin with the information most receive when starting a diet:

• In order to lose fat, you must be in a calorie deficit. This means you must eat fewer calories than you burn or burn more calories than you eat.  
• All foods have calories, all activities you do burn calories.  
• Your body will either have a neutral (no change in weight), negative (losing weight) or positive (gaining weight) energy balance based on your caloric intake and output.  Simplistically, as long as you're in a calorie deficit, you will lose weight.

These guidelines are summed up by this familiar energy balance equation:

Precision Nutrition 

This equation never stops working.  The laws of physics do not change, no matter how long you've been dieting.  The issue is the energy balance equation is more complex than presented.  Not every calorie eaten and burned can be accounted for through labels, logging and tracking.  It is either impossible or very expensive to know your exact calories in/out each day.

Calorie intake is affected by the following:

• Nutritional labeling discrepancies:  calorimetry is not fool-proof.  Nutritional labels and calorie values can be off by up to 25%.  
• Measuring discrepancies: think you're super slim-savvy using a measuring cup?  Think again.  Caloric values are always in terms of weight, not volume.  For example, a tablespoon of peanut butter is supposed to weigh about 15g.  If you scoop out an amount of peanut butter with a tablespoon and weigh it on a food scale, its weight is often closer to 30g (double the serving you think you're getting).  Using a food scale is far superior to using volume based measurements when tracking food.
• Digestibility of food: calorie labels state how much energy is in a food, not how much you absorb from that food.  You absorb more calories from foods that are cooked or processed.  For example, you will most likely absorb 100% of calories from a serving of almond butter, but only absorb about 70% of calories from a serving of raw almonds.  The more processed or cooked a food is, the more readily available its nutrients and calories are to your body.
• Gut bacteria:  the environment in your gut is a major player in your ability to absorb nutrients and breakdown food.  If food is not broken down properly and nutrients are not absorbed, your body may increase its calorie absorption in an attempt to receive more nutrients.  On an individual level, calorie absorption can vary by up to 25%

Considering the factors above, the 'energy in' portion of the energy balance equation will now look like this:

Precision Nutrition

There are also a multitude of factors affecting the calories you burn:

• Resting metabolic rate: 60% of the calories you burn each day are used just to sustain basic functions of living.  This number depends on body composition, age, sex, genetics, weight and gut bacteria.  RMR is usually higher in larger or leaner individuals.  RMR can vary up to 15% even among individuals with seemly identical characteristics.  For example, in a room full of 35-year-old, 200lb males, RMR can vary among subjects anywhere from 1,900 calories to 2,300 calories.
• Thermic effect of eating: 5-10% of your daily calorie burn comes from processing and digesting food.  The more food you eat, the more you burn.  You burn more calories digesting protein and minimally processed foods.  You will never out-burn the amount you eat through eating, though...nice try.  
• Physical activity: this one seems like a no-brainer, exercise burns calories.  Larger or leaner individuals will burn more calories than smaller or fatter individuals (muscle burns calories, fat does not).  However, the more you perform a specific exercise, the more you will adapt to it.  This means you will burn fewer calories each time you perform a specific exercise.  This is one reason why strength training is crucial to fat loss.  Strength training is adaptable and progressive over time.  Cardiovascular based activities have fewer variables to increase as your body adapts to them.  Read- you don't burn 500 calories every time you take spin class.
• Non-exercise activity thermogenesis:  NEAT is the calories you burn through standing, fidgeting, pacing, cleaning, etc.  NEAT varies from person to person and from day to day.

Considering the factors above, the 'energy out' portion of the energy balance equation will now look like this:

Precision Nutrition

Remember that cute, little 'energy in = energy out' equation from before?  Look how big s/he got:

 Precision Nutrition

Energy balance is even more complicated than this beefier equation.  Any of the variables above will affect other variables when increased or decreased.  Let's take a look at what happens when an individual decides to diet:

Eating less decreases calories in-->Thermic effect of eating decreases because less food is eaten-->RMR and exercise calories decrease if weight loss occurs-->NEAT calories decrease due to weight loss or lowered energy levels-->Nutrient absorption increases as weight loss occurs.

 Here is a real-world application of the above:

Mike is a 35-year-old, sedentary, 5'10, 200lb male.  His FitBit calculates that he burns about 2,500 calories each day.  He decides to eat 2,000 calories each day, creating a deficit of 500 calories.  Since there are 3,500 calories in a pound, he should lose 1 pound a week.

Mike begins to eat fewer calories-->Thermic effect of eating is lowered.  Mike loses 5 lbs in the first month of his plan-->RMR is lowered since he weighs less.Mike has not been strength training, so he loses some muscle along with his fat-->RMR is lowered.Mike lowers his calories more to keep losing weight, this makes him hungry and lethargic-->NEAT decreases.

After two months, Mike has still only lost 5lbs.  If he keeps decreasing calories, he will continue to burn fewer calories, especially if he loses more weight.
 The takeaway point here is: dieting doesn't cause your metabolism to self-destruct, the nature of creating a calorie deficit lowers metabolism right off the bat.  Individuals who have dieted down to a certain weight have adaptively slower metabolisms than individuals who started at that weight.

Before you get all doom-and-gloom, there are ways to keep your metabolism as high as possible during and after a diet.  Don't worry, grapefruit eating and sauna sitting are not on this list.

• Boost Thermic Effect of Eating: eat more protein, unprocessed foods and fibrous vegetables.  Instead of reducing calories when a plateau hits, try increasing protein and lowering carbohydrates to boost TEE.  
• Keep RMR from plummeting: add strength training to your routine 2-5 times a week and eat adequate protein to maintain or build muscle.
• Increase NEAT: add more walking and standing into your daily routine.  Take the stairs, clean your house, stop asking mom to do your laundry.  Track your steps, aim for at least 10,000/day.
• Increase physical activity: listen to Nike.
• Balance your gut: take a probiotic with at least 30 billion cultures (Garden of Life, Dotfit make good ones), eat yogurt and other fermented products like kombucha and kimchi.  Eat fruits and vegetables from a local garden, they contain prebiotics (gut substrate) from the soil.
• Decrease measuring discrepancies: This one is the most important!  The most common reason for fat loss plateaus is lack of diet adherence.  Log and weigh your food for at least 3 days to make sure you are actually eating the amount you're supposed to. 
• After you've reached your goal: slowly increase your calories each week to bring yourself back to maintenance calories.  Let's say you were eating 1,200 calories/day during your diet.  Start by increasing to 1,300/day and increase each week until you're at maintenance.  This method of 'reverse dieting' is crucial to ensure that you don't regain the fat you lost.  It is also an important method of boosting your metabolism (mainly through TEE) after a diet.

As you can see, fat loss is a complicated and non-linear process, understand what it will actually take for you to achieve your goals.  Remember, self deception causes more plateaus than so-called 'starvation mode.'  If your progress has stalled, review your information, check your methods and tighten up your plan before blaming your body.