You never lose weight in a straight line down. There will be good days and bad days, good weeks and bad weeks and typically the most dramatic change is earlier on for the simple reason that your body is not used to the changes forced upon it and, of course, there is much more to lose from. Most people that embark on a weight loss journey lose weight through the first 6-12 months and then there is plateauing, and some element of weight regain and unfortunately only about 16% of dieters keep their weight off long term, which would be considered a minimum of 1-2 years.

The definition of homeostasis is the tendency toward a relatively stable equilibrium. Your body loves homeostasis. It wants things to stay the same. Your body also loves energy, and likes to store it because it never knows if it will be there tomorrow. The DNA in your body contains the code for proteins, like insulin that have little changed in 200 million years. I am not suggesting that the DNA is static. It is not, there is an entire field of what’s known as epigenetics, which represents changes in the DNA that doesn’t affect the sequence of the code but can modify the code and change how it is expressed, in good ways, and in bad, but in obesity, mostly bad. The short answer to why you find yourself on a plateau, or regaining weight, is that your body, and by that, I mean the brain and DNA primarily, is designed to defend the fat mass, if it loses fat (energy) it wants it back. That is a gross simplification, but the four primary reasons for weight regain or plateauing after a loss of 10% or more of body weight are:

  1. There is a 20% increase in muscle efficiency at low to moderate activity. You might think, of course, because if I weigh 10% or more less, then it’s that much easier for my muscles to move me around; but it’s more technical than that. There are metabolic changes in the muscle fibers that account for that change.
  2. Deep inside your brain, the hypothalamus, there are neurochemical changes that occur which decrease satiety and increase hunger.
  3. Bioactive thyroid hormones (T3, T4, TSH) are all low, mimicking a sick euthyroid state. The levels decrease by about 12%, and so do the Leptin levels (one of the hormones promoting satiety).
  4. The Parasympathetic Nervous System (PNS), which is associated with relaxation/low metabolism sees an increase in tone of 75% whereas the Sympathetic system (SNS), which is associated with stress/high metabolism sees a decrease in tone of 45%. The end result of this impact on the PNS and SNS is a net decrease in metabolism.

So, in trying to put this all together, during the course of a day your Total Energy Expenditure (TEE) is the total of your Basal Metabolic Rate (BMR), which represents all the essential life processes, like making urine, beating heart, thinking, etc. plus the Diet Induced Thermogenesis (DIT), which is the energy required to absorb, digest and convert food to energy plus the energy expended in Physical Activity (PA). I hate to do this, but we need to break PA into Exercise Activity Thermogenesis (EAT) and NonExercise Activity Thermogenesis (NEAT). This is important because all the changes I referenced above impact every component of the TEE; but, of all the components of the TEE (TEE=BMR+DIT+EAT+NEAT), the one that accounts for roughly 70% of the decline in overall energy expenditure is NEAT, unless there is an overly large component of exercise, like training for a marathon.

Energy Balance

The cold hard truth that has been well documented is that after a significant weight loss your metabolic rate decreases by 300-400 calories per day below what it should be at you brand new goal weight, or plateau weight (if you’ve lost more than 10%). What this means is that if you lost weight from 300 lbs. to 250 lbs. your metabolism needs would be 300-400 calories less than someone already at 250 lbs. who never lost weight. Not fair. It isn’t. I’m sorry. That’s life. Now, lets do something about it.

The first thing to do is to not blame yourself. What I have described are specific physiological changes that are beyond your control. Your job is to respond to those changes in a knowledgeable and responsible fashion. For simplicity’s sake, I’ll list some thoughts/suggestions that are all secondary to the first thing.

  • In general, you lose weight by diet, and you maintain weight-loss with exercise.
  • In general, the easier way to lose weight is with a mild to moderate caloric restriction of about 500 calories/day.
  • The decrease in satiety and increase in hunger from the neurochemical changes in the brain is difficult, but can be countered by knowledge, resolve, behavioral modification, and if necessary, pharmacology (wt. loss medications). Interestingly, bariatric surgery, such as a sleeve gastrectomy or gastric bypass, results in metabolic changes that largely counter the neurochemical changes seen after a diet/medical weight-loss program w/o surgery.
  • The decrease in thyroid function and leptin levels and changes in the autonomic nervous system (parasympathetic and sympathetic) are interrelated. Some of the effects can be reversed with leptin administration in clinical studies; but this has not yet made its way into widespread clinical practice. Still, I would think that checking both thyroid function and testosterone (in males) might be worthwhile after a significant weight loss, and it may be that addressing any deficiencies would be of benefit.
  • Accountability is always important. After a successful weight loss, it may be that you’ve stopped counting. It is always helpful to reassess as usually you eat more and exercise less than you think you do. All calories do count towards energy storage; the salad dressing, the toppings, and although nuts and almonds and peanut butter and coconut are all good fats, they are very energy dense (all fat is) and still. Do. Count.
  • I like low-carb diets, it is what I generally do although I am rarely ketogenic these days, but for many, with keto, anything goes, relative to fat, like bacon, Spam, prime rib, a nicely marbled rib-eye, as long as it’s zero carb, it’s good. It’s not, as a matter of routine. I had a prime rib last week and some bacon in a turkey wrap just this noon, but it was not the King cut and the bacon was an unsatisfyingly small amount. It is still a good idea in low-carb eating to choose the protein sources lower in fat (poultry, fish, lean cuts of beef, bison, lean hamburger).
  • If NEAT (Non-Exercise Activity Thermogenesis) accounts for 70% of the decrease in the Total Energy Expenditure, increase it as much as possible. This means using stairs instead of elevators, parking at the far end of the lot instead of close to the door, standing at your desk, reading a book on a recumbent bike rather than on the sofa, watching the news on a treadmill, doing five deep knee bends or one-legged squats between colonoscopies (if you’re a Gastroenterologist), tap your feet to music, any movement or use of your native body weight counts.
  • There are three macronutrients: Carbohydrate, Fat, Protein. If you eat less of one, you will eat more of the other two. By choosing leaner sources of protein, you will likely eat a larger portion size towards satiety, which is ok, as long is it’s not protein all day every day, but you will be eating more protein than fat and protein has the highest DIT (Diet Induced Thermogenesis) of the three, meaning that there is a larger energy cost to metabolizing ingested protein when compared to carbohydrate and fat.
  • Studies have shown that those people who maintain weight loss long-term account for the 300-400 calorie daily decrease in their metabolism by eating about 150 calories less and exercising about 250 calories more. This was their pattern, they didn’t set out to specifically account for 400 calories, they didn’t know what you know now, it’s like their bodies figured it out, or they did, on their own.
  • Are you on any medications that impair weight-loss or promotes weight gain? Common ones include anti-depressants, other psychiatric medications, B-blockers; there are many more medications that promote weight gain than promote weight loss. You can research these yourself with a search engine, and if you get a hit: Don’t stop your medication. See your doctor.
  • The improved efficiency of muscle is seen only in low-impact, aerobic activity at low-moderate levels, like swimming, walking, riding a bike.
  • Moderate to high level, higher impact aerobic activity, and resistance training are less efficient.
    • If you are riding a bike or walking, to have the same impact you are going to have to increase time and distance by 20%.
    • Adding resistance training 2x/week should increase your metabolic rate. You may not lose as much weight, but you will lose inches.
    • If you are taking medications or have orthopedic issues or hypertension or heart disease, you should get clearance from your doctor.

I’ll stop with the list for now. I’ve always thought Knowledge is Power. Well, here’s your power, and if all this fails, don’t despair, you simply need more help. There will be some that may need pharmacological management or bariatric surgery, but you don’t necessarily start there. You start with what makes sense, if that doesn’t work, then you look at the other things. As discouraging as it may sound, the weight-loss induced decrease in metabolism, it is encouraging that so much more is known about the problem of obesity than only a few years ago, and it remains a continually active area of research. There are exciting new medications just around the corner, some are already here; and bariatric/metabolic surgery can reverse diabetes and other obesity-related illness. So, if you are plateaued or starting to regain weight after reaching a goal, please consider:

  1. Counting your calories, again. Make sure you’re in a negative energy balance.
  2. Lift weights or other inefficient exercise.
  3. Check your medications to see if you’re on one that impacts your weight, see your doctor, ask if checking your thyroid function or testosterone levels is appropriate.
  4. If you have been on your weight-loss journey alone, congratulations on your commitment and courage to change, but if you find you are still struggling, you could consider a more structured program that has the inclusion of behavioral management and closer clinical follow up.