The 6 Weight-Loss Tips That Science Actually Knows Work

Some of the weight loss articles out there these days are getting a little nutty. New scientific studies that shed light on how metabolism works are wonderful and valuable in their own right, but when findings get morphed into magical new “tips” for losing weight, something’s amiss. Some recent pieces in prestigious journals, which have sought to dispel the myths of weight loss and of the individual diets themselves, suggest that the medical community is also getting tired of the hype and the unfounded assumptions that permeate the public discussion.

When it comes down to it, the things we know to be true about weight loss are relatively simple, and certainly few. They’re also extremely effective when actually carried out. So, from the researchers who have studied this stuff for decades, here’s pretty much everything we know about weight loss today, whittled down to six points about how the body actually gains, loses, and maintains its weight.

1. Dieting trumps exercising

We hear a lot that a little exercise is the key to weight loss – that taking the stairs instead of the elevator will make a difference, for instance. But in fact it’s much more efficient to cut calories, says Samuel Klein, MD at Washington University’s School of Medicine. “Decreasing food intake is much more effective than increasing physical activity to achieve weight loss. If you want to achieve a 300 kcal energy deficit you can run in the park for 3 miles or not eat 2 ounces of potato chips.” It’s as simple as that. Some studies have borne out this dichotomy, pitting exercise against diet and finding that participants tend to lose more weight by dieting alone than by exercise alone. Of course, both together would be even better.

The problem is that when you rely on exercise alone, it often backfires, for a couple of reasons. This is partly because of exercise’s effects on the hunger and appetite hormones, which make you feel noticeably hungrier after exercise. “If you walk briskly for an hour and burn 400 kcal,” says Klein, “and then have a beer and a slice of pizza afterwards because the exercise made you feel hungry…you will eat more calories than you have burned.” It may not always be beer and pizza, but people do tend to naturally compensate for the calories they expend.

“This is an adaptive system,” adds David Allison, PhD. “For every action there’s a reaction; that’s a law of physics, not of biology, but it seems that it also works in biological systems. This is why we often overestimate quite radically an effect of a particular treatment.” He points out that public health campaigns that, for example, urge people to take the stairs instead of the elevator or go on a nightly stroll – or, for that matter, even eat fewer calories – are unlikely to work, since they may fail to take into account the body’s compensatory mechanisms that can totally counteract the effect.

The other problem with exercise-without-dieting is that it’s simply tiring, and again, the body will compensate. “If the exercise made you tired so that you become more sedentary the rest of the day, you might not experience any net negative energy,” says Klein. Some of the calories we burn come from our basic movements throughout the day – so if you’re wiped out after exercise, and more likely to sit on the couch afterwards, you’ve lost the energy deficit you gained from your jog.

2. Exercise can help fix a “broken” metabolism, especially during maintenance

“People used to come into the doctor’s office and say, ‘My metabolism is broken!’” says James Hill, PhD, at the University of Colorado. “We never had any evidence that it actually was, until recently. We were wrong – it was!” While exercise may not be as important for weigh loss as calorie restriction, as Hill says, it’s important in another way: It begins to repair a broken metabolism.

“A lot of what we know in this area comes from NASA, of the bed-rest studies,” he says. “Within a couple of days of non-activity, the metabolism becomes inflexible. You start moving again, and it does start to change.” Your metabolism may not ever go back to “normal” (more on this below), but the evidence indicates that it can indeed pick up again, in large part through moving your body every day.

This is a large part of why exercise is critical in the maintenance phase, which is well known to be more difficult than the weight loss phase. Essentially, it buys us some wiggle room, says Michael Jensen, MD at the Mayo Clinic. “Exercise is very, very important for maintaining lost weight, and people who are not physically active are more likely to gain weight. We think it’s partly because in the extra calories burned from physical activity, you have a bit more flexibility in food intake, so you’re not so much relying on ridged changes in eating habits; it makes it more tolerable.”

3. You’re going to have to work harder than other people – possibly forever

Though exercise can help correct a metabolism that’s been out of whack for a long time, the grisly reality is that it may not ever go back to what it was before you gained weight. So if you’ve been overweight or obese and you lose weight, maintaining that loss means you’re probably going to have to work harder than other people, maybe for good. “The sad thing,” says Hill, “is that once you’ve been obese or not moving for some time, it takes a little more exercise to maintain. It doesn’t come back to normal.” It’s not a pretty reality to face, but coming to grips with it is important, he says, so that you won’t get frustrated when you discover that you have to do more work over the long term than your friend who was never overweight.

Building muscle can help your body burn a few more calories throughout the day, but it’s also likely that you’ll have to work harder aerobically in the long run. “It’s not fair, but that’s the way it is,” adds Hill. “Once you understand it, though, you know it and it’s better. Because you can work with it.”

4. There’s no magical combination of foods

We often think that if we can just discover the “right” combination of foods, we’ll magically lose weight or maintain what we’ve lost. There are low-fat diets, low-carb diets, low glycemic diets, Paleo diets, and a lot of iterations of all of these. Jensen points out that in fact there doesn’t seem to be any “right” diet, and there doesn’t seem to be any evidence that one particular diet will work better with an individual’s specific metabolism. “The big myth out there,” he says, “is that there’s a magical combination of foods – be it protein, vegetarian, and what have you – that’s going to be unique because of its unique interaction with your metabolism. We know pretty much that any diet will help you lose weight if you follow it. There’s no magic diet. The truth is that ALL Diets will work if you follow them.”

5. A calorie IS a calorie!

And for energy balance, it’s the number of calories that matters. Weight loss on the Twinkie Diet proves this principle: Last year, Mark Haub at Kansas State University lost 27 pounds eating junk food. And this is pretty good proof of concept, says Yale University’s David Katz, MD, who has written extensively on the futility of the “is a calorie a calorie?” debate.

It’s certainly true – at least in theory and sometimes in practice – that all calories are created equal. “From the standpoint of body weight,” adds Marion Nestle, PhD, of NYU, “a calorie is a calorie no matter what it comes from. You can gain weight eating too much healthy food as well as unhealthy. From the standpoint of health, it’s better to eat your veggies…. It’s just a lot easier to overeat calories from junk food than healthy food. But it can be done.”

But the source of calories obviously matters for other reasons. One, says Katz, is that “the quality of calories is a major determinant of the quantity we ingest under real world conditions.” First of all, no one overeats veggies, so on a practical level, that’s a non-issue. “But where the calories come from does matter in that they influence satiety,” he adds, and this is partly psychology and partly biology. In fact, the food industry has carved out a whole new area of food science to study the “bliss point,” in which foods are created to increase the amount it takes to feel satiated and full. On one hand, says Katz, “we have the ‘bliss point’ science to tell us that the food industry can process foods to increase the calories it takes to reach satisfaction. We have the reciprocal body of work, including the Harvard study of the ONQI, showing that ‘more nutritious’ means, among other things, the opportunity to fill up on fewer calories.”

It’s true that types of foods you eat may, over time, affect your metabolic profile, so they may also matter in this way, but when it boils down, sticking to any reduced-calorie diet will create the energy deficit needed to lose weight. So the point is not to question what a calorie is, but rather to understand that we need to “trade up” our foods, says Katz – exchange the very dense, calorie-packed foods for foods that are less calorie-dense and more nutritionally dense: these are the ones that are bulkier, less energetically rich, have more or higher quality protein, are lower on the glycemic index, and more fibrous.

6. It’s all about the brain 

As my colleagues have reported (here and here), when it comes down to it, it’s not the body or the metabolism that are actually creating overweight or obesity – it’s the brain. We all know intuitively that poor decisions are what make you gain weight and better ones are what make you lose it. The problem is that over time, the poor decisions lead to significant changes in how the brain governs – and, amazingly, responds to – the hunger and satiation processes. Years of any kind of behavior pattern lay down neural tracks, and overeating is no exception.

The good news is that there’s increasing evidence that the brain can, in large part, “fix” itself once new behavior patterns emerge (i.e., calorie restriction, healthy food choices, and exercise). While there may be some degree of “damage” to the brain, particularly in how hunger and satiety hormones function, it can correct itself to a large degree over time. The key is that the process does take time, and like any other behavior change, is ultimately a practice. “We want to change behavior here,” says Hill. “Anyone that tells you it’s going to happen in 12 weeks, that’s bogus. We’re trying to rewire the brain. Neurobiology has told us so much about what’s going on in weight gain and weight loss. It takes a long time to develop new habits, rituals, routines. This takes months and years. But it will happen.”

The 6 Weight-Loss Tips That Science Actually Knows Work


Putting the Science behind Exercise – Workout Smarter, Not Harder

Athletes tend to push themselves 120 percent while exercising because their main objective is to jump higher, run faster or become stronger. If your main objective is weight-loss, you do not need to push yourself this hard. What you need to do is find an appropriate intensity that will maximize your body’s ability to burn calories, specifically fat calories.

For some of you, this may be a difficult concept to grasp because you have always had the “no pain, no gain” mindset. The reality of maximizing your weight-loss is to work smarter, not harder. Yes it is true; you do not have to “kill” yourself in order to lose weight. In fact, your body is actually better at burning fat at low to moderate intensities of activity, especially if you are just starting to exercise. Although most athletes tend to be leaner, you will be delighted to know that you do not have to train like an athlete to maximize your body’s ability to burn fat and ultimately become leaner.

How Your Body Burns Calories for Fuel

First, let me describe how your body uses fuel for activity and movement. Throughout the day, your body uses calories obtained through food for its fuel. Most of you understand that if you consume more food than your body uses as fuel, you will ultimately gain weight, and if you consume less food than your body burns, you should ultimately lose weight. What you may not know is exactly what kind of food the body uses as fuel.

There are three different fuel sources, and your body generally uses two of them: fat and carbohydrates. Consider these two as your primary fuel sources. The third fuel source is protein. Protein is not an efficient fuel source. Protein’s main purpose is to build and repair tissue, not to provide fuel or energy. Although, eating protein is important for people trying to lose weight because they need to preserve their lean muscle through the weight-loss phase.

The idea is to prevent the body from tapping into lean muscle mass for fuel during the caloric restriction phase of any diet. This is essential because lean muscle helps stoke the metabolism because it takes more energy to sustain lean muscle versus fat mass.

Fat and Carbohydrates: Your Body’s Two Main Fuel Sources

Okay, enough about protein. What about fat and carbohydrates? I mentioned that these are the fuels we need to burn in order to go about our daily lives. Let’s start with fat, since it is really what most people are concerned with. Fat is utilized both at rest and during activity. How you metabolize or burn fat at rest is most directly related to what you eat; your body will burn what you feed it.

The analogy of your body being like a car should help explain this concept. If you put premium unleaded fuel in your car, that is what it is going to burn. By the same token, if you put regular unleaded fuel in your car, it has no choice but to burn the regular unleaded fuel. Your body works in a similar fashion. If you eat a diet rich in fat, it will burn a majority of its calories at rest from fat. Similarly, if you eat breads, pastas, fruits and vegetables, your body will burn a majority of carbohydrates at rest.

Genetics and a Healthy Diet Play a Part

Now, it does not always work out exactly this way because our bodies consist of tiny components called genes. I am sure you realize that part of the reason you may be the way you are is because of your genetic makeup, or heredity. In other words, some of us were simply born fat burners.

Yes, we have all met these people. You know, the ones that can sit around the office and munch on donuts in the morning, eat out for lunch every day, enjoy a candy bar in the afternoon, and never gain a pound. You probably “hate” these people. And then, others are just good carbohydrate (carb) burners. Their bodies “want” to burn carbohydrates and they hardly burn an ounce of fat at rest. You can “thank” your parents, grandparents, aunts and uncles for these traits; however, if you are not a born fat burner, do not dismay because you can do a lot to combat some of those non-fat burning traits you inherited.

One of the fastest ways to burn more fat at rest is to eat a well-balanced diet. If you eat a diet consisting of the right amount of carbohydrates, fats and protein, your body will burn about 60 percent of your calories from fat and about 40 percent from carbohydrates in a resting state. That is not a bad ratio of fat burn, simply from eating sensibly.

Diets that are high in protein and low in carbohydrate will significantly help create an even better fat-burning body. These diets essentially force your body to burn fat because you are not consuming the easily digested carbohydrate and the body does not like to use protein for fuel. Thus, the body turns to the stored fat and begins to break it down for fuel. This process is called ketosis. The body breaks down fat to produce glucose and a byproduct, called ketones, to use for fuel.

The Body Burns Fuel Differently at Different Times

You may be wondering what “at rest means.” It refers to a resting state, as opposed to a physically active state. When you are exercising, your body burns fuel a bit differently. What type of calories you burn at rest has everything to do with your diet and genetics, whereas what type you burn while exercising has everything to do with your fitness level. Generally speaking, your body will burn fat or carbohydrate for fuel during exercise just as it does in a resting state, but your body will burn fat better at low to moderate workout intensities. The more intense your exercise, the more carbohydrates your body will burn. The reason for this is because it takes a lot longer to break down and metabolize or burn fat.

The bottom line is, you will burn a greater percentage of fat exercising at lower intensities. This is especially the case for those of you that are just starting an exercise regimen. Great news for anyone trying to lose weight – you do not have to “kill” yourself in order to lose fat pounds.

Keep in mind that the body must utilize oxygen in order to burn fat. Aerobic exercise basically means exercise involving the intake of oxygen. When you exercise aerobically, you are utilizing a large amount of oxygen to burn calories. Conversely, anaerobic exercise means exercising at a level at which oxygen debt occurs because the need for oxygen exceeds the capacity of the circulation to supply it. This generally occurs with short bursts of high-intensity exercise such as a 100-meter dash, vertical jumps, power lifts, or the explosiveness of a defensive lineman at the snap of a football.

When the body is in an anaerobic state, it is only capable of burning carbohydrates. The best thing about this whole process is that you can actually make your body more efficient at burning fat at higher intensities and longer durations through training, specifically heart rate training. This should ultimately be everyone’s goal. If you are disciplined in training specifically to create the best fat-burning body possible, you will inevitably have an easier time losing weight and ultimately be able to maintain a healthy weight once you achieved your target weight. This helps explain why fit people tend to be leaner. They have created a body that is very good at burning fat; therefore, it is easier for them to manage their weight.

Let me explain how your body uses carbohydrates for fuel. Carbs are the preferred fuel source to some degree. The reason for this is because carbs are usually abundant in our bodies and most people ingest a large number of carbs daily. In fact, the body even stores carbs in the liver and muscles. These stored carbs are called glycogen. As you begin to move, your muscles can easily use this glycogen for energy. This also explains why your body will resort to burning more carbs when you exercise at higher intensities. More intense exercise requires quick energy, so the body resorts to burning carbs because it can get to them faster and break them down more quickly than the other two macronutrients (fat and protein).

This is great news, right? You are probably thinking, “Yeah, yeah… but how do I do it? How do I exercise to create the most efficient fat-burning system? Do I just start moving, and if so, for how long, how frequently, and how strenuously? Should I walk, bike, swim or lift weights?” These are all great questions.

Benefits of Heart Rate Monitoring and Metabolic Testing

Aside from proper diet, cardiovascular exercise is the main support on which to lean for weight-loss, specifically fat-loss. The key is to know the point (exercise intensity) at which your body is most effective at burning fat. This is where heart-rate monitoring comes into play. Most of us have heard of people using a heart rate monitor while exercising. The reason you would want to do this is to ensure that you are training at the optimal intensity level to burn fat most efficiently.

The point at which you are most effective at burning fat is considered to be your target heart rate, or aerobic base. It is the level of intensity, measured in beats per-minute, at which your body can burn the most number of fat calories per-minute. This is important to know if your main objective is fat-loss.

Now, everyone is different as to the point or exercise intensity that they are most efficient at burning fat. Generally speaking, you will burn fat better at those low to moderate intensities, but if you really want to be specific and put the science behind your workouts, you should get assessed through metabolic testing. This is the most effective method of measuring one’s aerobic base or maximum fat burning capacity. Check your local health clubs to see if any of them offer this testing, also known as indirect calorimetry, maximum oxygen update, or O2 testing.

Summing it All up

You might say, “Yes, but this goes against everything I have ever known or been told. I always thought you had to be huffing and puffing, or you were not really doing any good.” It is important to point out that there is a fine line here. The harder you work, the more total calories your body will burn; however, several problems come into play.

Most of you will not able to sustain this level of intensity, and it is fairly hard on your joints if you have not exercised consistently for some time. The other important consideration (and possible problem) is that you will be burning a greater percentage of carbs. You might be thinking, “Well, a calorie is a calorie, is a calorie, right?” Well, not exactly.

Keep in mind that if you are combining your new exercise with a sensible diet that is generally low in carbs and high in lean protein (a very popular and effective diet for those trying to reduce their weight), you are really not consuming many carbs. So if you are not eating many carbs and you have a whole lot of body fat to tap into, why would you want to burn more carbs through exercise? This would make it that much more difficult to stay on your diet after your workout.

If you burn a bunch of carbs during exercise, your body will tend to crave carbs post-workout, especially because you have been restricting them – not to mention that the fat you were trying to burn off during exercise is still hanging on, literally. This is not what you want to accomplish. You can get yourself into a vicious and frustrating cycle by trying to exercise like this. The idea is to force your body to burn fat both through exercise and diet. If you are working hard in the gym, be sure you are burning and wasting away fat, not time.

the Science behind Exercise