Chapter 1 — Why Do You Want to Lose Body Fat?
If you don’t know where you’re going, you can’t decide which way to aim. So before you change anything, ask yourself why you want to lose body fat. Is it to change the way you look, or the way you feel? What habits are you willing to take on? Can you keep them up? And will they make your life better?
If getting leaner were a sure way to feel better about yourself, the people who push it the furthest would be the happiest people around. They usually aren’t. One review found that bodybuilders have high rates of muscle dysmorphia, where you believe your body isn’t muscular enough no matter how it looks. It’s linked with anxiety, depression and perfectionism, and with lower self-esteem.
Your happiness isn’t guaranteed to go up when your body fat goes down. You can spend your whole life trying to change your body and never reach that point of happiness. None of this is meant to talk you out of losing fat. Carpenter just wants to make sure you aren’t chasing the wrong thing. And if you do go after it, it helps to know why it’s so much harder for some people than for others.
Chapter 2 — Don’t People Just Need More Willpower?
Some people move up in their careers faster than others with the same effort. Maybe they went to the best private schools, or a parent owns the company. They still have to work hard. But if they find it easier, that doesn’t mean they wanted it more. Weight works the same way. Some people never struggle with their weight, and that doesn’t mean they have more willpower.
Global obesity has almost tripled since 1975. One of the biggest reasons seems to be our food environment. We’re surrounded by more and more high-calorie, ultra-processed food. A medium apple has about 100 calories. A single doughnut can have a few hundred. Which one is easier to eat a lot of?
Distance matters too. In one study, people ate more from whichever bowl was within arm’s reach, apple slices or popcorn, even though they rated the popcorn as tastier. In another, moving a bowl of M&Ms from 70 centimeters away to 20 got more people eating them. And people who live near more fast food restaurants are more likely to weigh more. The easier it is to eat something, the more likely someone will eat it. You can use that to your advantage by making the foods you want to eat the convenient ones.
Variety pushes you to eat more. Feeling full is tied to a specific food, which is why you can be too full for your main course and still have room for dessert. You get tired of one food, but a table of different tasty foods makes it easy to keep going. In one study, people ate about a third more when their sandwiches came with four different fillings instead of one.
Portion size works the same quiet way. In another study, people were served a different-sized sandwich each week. With a 12-inch sandwich instead of a 6-inch one, men ate 56 percent more calories and women ate 31 percent more. And they didn’t feel any fuller. Bigger portions get you to eat more without you noticing.
Some people think shaming someone about their weight will push them to change. Most research says it does harm. People who’ve faced weight stigma are more likely to avoid exercise, so the friend who makes fat jokes is probably making you less likely to work out. In one study, people who saw themselves as overweight read an article called “Lose Weight or Lose Your Job.” Afterward, they ate more snacks and felt less able to control their weight.
Working with clients taught Carpenter that instead of just telling people to eat less, it helps to ask what makes them eat more in the first place. Stress is a big one. In one study, 73 percent of people said they snacked more when stressed, and they reached for chocolate, sweets and cake instead of meat, fish, fruit and vegetables. Not everyone reacts the same way, though. Some people are “stress eaters,” and others are “stress fasters.” Boredom matters too. People given a boring task ate more of the crackers left out for them than people given an interesting one.
A review of 33 studies concluded that negative emotions do cause people to eat more. Depression and obesity also feed each other, with each one raising the risk of the other. So yes, weight loss comes down to calories in versus calories out. But lots of things affect how easy that is for each person. Knowing them keeps your expectations realistic and helps you plan around the hurdles. And to plan well, it helps to understand how the calorie math actually works.
Chapter 3 — The Fundamental Concepts of Weight Loss
As you lose weight, your body burns less energy, because a lighter you needs less fuel. Say you need about 2,500 calories a day to stay the same weight, and you start eating 2,000. You begin with a 500-calorie deficit and lose weight. But as you get lighter, you burn fewer calories through exercise and everyday movement. You also burn a little energy just digesting food, called the thermic effect of food, and eating less means less of that too. At some point, 2,000 calories isn’t a deficit anymore, and your weight loss stalls.
If you remember one thing, make it this: when you change how many calories you eat, you also change how many you burn. That’s why the speed of weight loss is so hard to predict.
Protein has the highest thermic effect. Your body burns about 20 to 30 percent of protein’s calories digesting it, compared with 5 to 10 percent for carbs and 0 to 3 percent for fat. That may give high-protein diets a small edge. But eating a bit more protein to burn more calories is like getting a few extra miles out of your gas tank. You won’t really notice. Calories are only part of the story, though. What they come from matters too.
Chapter 4 — Food Quality vs Food Quantity
In one study, people ate either a “whole food” sandwich of deli cheese on multigrain bread, or a “processed” one of cheese slices on white bread. After the processed sandwich, their bodies burned 50 percent less energy. If every meal you eat burns half as much afterward, that could add up. It shows one way ultra-processed food could be more fattening, calorie for calorie.
Another study ranked how filling foods are. People ate the same 240-calorie portion of 38 different foods, then ate from a buffet two hours later. The most filling foods were high in protein, fiber and water, and came in bigger servings. Plain boiled potatoes, white fish and porridge came out on top. Croissants, cake and doughnuts came in last. This idea is called energy density: how many calories are packed into a given amount of food.
Low-energy-density foods help because your hunger responds to the weight and volume of what you eat. A big plate can satisfy you more than a small one with the same calories. In one study, people ate fewer cheese puffs when the puffs were pumped full of more air, and they didn’t feel any hungrier. Vegetables work the same way. If broccoli takes up more of your plate by replacing some of the beef and rice, you’ll likely eat fewer calories without feeling hungrier.
Speed plays a part as well. When people could eat as much as they wanted of an ultra-processed or an unprocessed diet, they ate the ultra-processed food about 50 percent faster. And eating faster leads to eating more, maybe because you get more down before your body tells you you’re full.
So a calorie deficit is still required for weight loss. But what you eat shapes how hungry you feel, so food quality matters a lot. Choosing unprocessed foods with low energy density is one of the best-studied ways to keep hunger in check. Still, a good diet you can stick with beats a perfect diet you can’t.
Chapter 5 — How Quickly Will I Lose Weight?
The scale isn’t the only way to measure progress. If you’re eating more fruit and vegetables, less ultra-processed food and less alcohol, and you’re hitting your activity goals, you know you’re taking real steps for your health, even without a big weight goal.
So is faster or slower better? One review of 29 studies found that people who lost weight fast at first kept more of it off in the long run. Quick results may be motivating. The fast group ramped up their activity, and the slow group didn’t. Watching the scale drop feels like a reward. The fast plan was also simpler, with ready-made meal replacements that took out the guesswork. Sometimes simple advice works better, even when it looks extreme.
But if you care about muscle, strength and performance, dieting slowly is better. It takes longer, but you can keep making progress in the gym. Some people would rather rip the Band-Aid off and accept they won’t set any personal bests for a while. One trial found that by the end, fast and slow dieters were basically the same in body composition, hunger and metabolism. A review of seven trials leaned slightly toward slower loss. Neither speed is a clear winner, so pick the one you can keep up. Diet sets the pace. The next question is what exercise adds.
Chapter 6 — What Difference Does Exercise Make?
For your health, moving matters a lot. Exercise lowers the risk of more than 25 chronic conditions, including heart disease, type 2 diabetes and high blood pressure, and it slows the decline that comes with age. The guideline is 150 to 300 minutes of moderate exercise a week, or 75 to 150 of vigorous exercise. Ideally that means cardio plus at least a couple of strength workouts. But you don’t have to hit that to get healthier. Even walking more is linked to living longer.
For fat loss, though, exercise isn’t as powerful as people think. It’s much easier to eat calories than to burn them. Grab a chocolate bar or even a fruit smoothie on the way out of the gym, and you might take in more than you just burned. That’s why cardio alone often gives disappointing results. For weight loss, think of diet as your main course and exercise as the side dish.
The details matter less than people think, too. A review of dozens of studies found that how hard you train barely matters for fat loss. Fasted cardio, done before you’ve eaten, doesn’t burn more fat either. So choose what fits your life. If you’re short on time, shorter and harder workouts are efficient. If you’re new, start gently.
One principle does matter: progressive overload. It means doing a little more over time, so your body keeps adapting. You can lose fat without exercise, but this helps you keep muscle while you diet. If Carpenter could announce one piece of fitness advice over a megaphone, it would be this: find exercise you enjoy enough to stick with, then try to get better at it over time.
What looks best on paper doesn’t matter if you hate it and quit. So play to your own psychology. Do you like working out alone or with a friend? Does tracking your workouts keep you going? Mornings or lunch breaks? Outside or inside? Weights or body-weight exercises? Build it around your life.
Chapter 7 — How Difficult Is Maintaining Long-Term Weight Loss?
Here’s the secret most weight loss books don’t talk about. Losing weight in the short term is fairly simple, but keeping it off is hard, and long-term success rates are notoriously low. People don’t like to mention it, because it takes the magic out of whatever diet they’re selling.
Some programs do better. In one long-term hospital program, nearly half the participants kept the weight off. It came at the problem from every side. People got a low-calorie diet, plus exercise targets that rose over time, nutrition lessons and therapy for self-control and relapse. They saw a psychologist at least ten times. They learned to track what they ate and how much they moved, which the researchers saw as the most important piece. When someone struggled, the program helped them problem-solve, like finding a workout partner.
So why did the other half regain the weight? A big reason was eating when they weren’t hungry, driven by loneliness, depression and anxiety. People who eat to cope with hard emotions may need help with those emotions more than they need another diet.
Another reason people regain is that they don’t adjust as they go. At some point your smaller body needs fewer calories, and you’re not in a deficit anymore. Plateaus are normal and nearly unavoidable. But many people get discouraged when the scale stops moving and go back to their old habits.
Enjoyment changes everything. Some people love walking because it’s time alone with an audiobook. Others jog with a friend, lift because they like getting stronger, or box to let off steam after a hard day. Food works the same way. Diets that suck all the joy out of your life won’t last. People can stick to strict diets when the reason runs deep, like going vegan for ethical reasons or eating halal for religious ones. But forcing yourself through a plan you hate just to lose fat rarely lasts.
The people who keep weight off tend to share some habits. They eat fewer calories, often from a lower-fat diet, eat more fruit and vegetables, stay very active and keep an eye on their weight. Motivation, goal setting and enjoying the process matter too, and so does a plan for emotional eating.
Chapter 8 — What Diet Will Work for Me?
Start with a distinction. You can lose a pound of fat and gain a pound of muscle, and the scale won’t budge, even though your body has changed. Losing weight and losing fat aren’t quite the same thing. And counting calories isn’t the same as calories mattering. One person saves money by tracking every dollar. Another just stops buying certain things. Only one counted, but both spent less than they earned.
So which diet is best? One review looked at 48 studies with 7,286 people, covering Atkins, South Beach, Zone, Weight Watchers and more. Which one won? None of them. The differences were too small to crown a winner.
High-protein diets come closest to an edge. One review found they led to a little more weight loss than moderate-protein diets, even with the same calories. For people who lift, about 1.6 grams of protein per kilogram of body weight a day seems to be plenty for building muscle, and more doesn’t add much.
What about cutting carbs? A lot of research shows low-carb diets lead to more weight loss than low-fat diets. But people who cut carbs tend to eat more protein, so which one is doing the work? One study tested this with four groups on the same calorie deficit for a year, mixing normal or high protein with normal or low carbs. Both high-protein groups lost more fat. The carbs didn’t seem to matter the same way. So low carb wins for weight loss, especially early on, but for fat loss it’s a draw. If you love high-carb foods, a low-carb diet could be a disaster for you. Get enough protein, then split the rest between carbs and fat however you like.
Fasting gets the same kind of hype. One trial found that eating every other day wasn’t better than cutting calories every day for sticking with the plan, losing weight or keeping it off. Reviews mostly agree that intermittent fasting works for weight loss but isn’t better than eating less every day, and it can bring more side effects, like dizziness, mood swings and low energy. Eating only during certain hours looks similar. When calories are matched, the results come out very close. Fasting is just a different vehicle that takes you to the same destination: eating fewer calories.
That’s good news, because you have a lot of freedom about when you eat. If you’re not hungry in the morning, you don’t need to force down breakfast to “kick-start your metabolism.” Eating later is fine. So is skipping breakfast and eating a bigger lunch and dinner.
Diets built around lean meats, fish, fruits, vegetables, nuts and eggs, like paleo, often lead to weight loss and better health, even when people eat as much of those foods as they want. The Mediterranean diet is widely seen as healthy, and its focus on quality often nudges you toward fewer calories. You don’t have to follow either one strictly. Just lean on the same kinds of foods, like fruits and vegetables, whole grains, fish, beans, nuts and olive oil, and let them crowd out the ones you want less of.
Vegetarians weigh less on average, but not just because they skip meat. One study found they also ate more beans, whole grains, fruits and vegetables, and less fried food, alcohol and sugary drinks. Other research found they smoked less and exercised harder. Their whole lifestyle is often different. Plant diets can build muscle just as well with good planning, but it’s easier to fall short on protein, and animal protein is probably at least slightly better for muscle. You can borrow the helpful plant-based habits, like more fiber and less fried food, even if you eat meat.
How strict should you be? Rigid restraint means all-or-nothing food rules. Flexible restraint means no food is totally off-limits. One study of women in a weight loss program found that flexible restraint did a better job of predicting long-term weight loss. Rigid rules can backfire. That’s part of why more people are turning to intuitive eating, which drops diet rules and listens to your own hunger and fullness. It’s linked with better body image and self-esteem. You can mix the two. Eat protein several times a day and plenty of nutrient-rich foods, and let your hunger guide how much you eat.
The simplest advice would be to never eat anything ultra-processed. But in a world full of it, banning it forever can blow up in your face. Nobody thinks one salad will give them a six-pack, so why act like one slice of cake will ruin your health? Your overall calories and diet quality matter far more than any single food.
Chapter 9 — What Is the Best Meal Frequency?
Once you’ve chosen what to eat, there’s the question of how often. One research team concluded that “there is little robust evidence that reducing meal frequency is beneficial.” In plain terms, there’s no strong evidence that you need a certain number of meals. So go with what you prefer.
Chapter 10 — Sugar: The Truth Behind the Controversy
Sugar gets blamed for a lot. But everything depends on the dose, even good things. Too little exercise is unhealthy, but so is too much. Not enough water will kill you, and so will far too much. Sugar is no different.
In one trial, two groups ate the same calories, protein, carbs, fat and fiber. The only difference was sugar: 25 percent of calories for one group and 10 percent for the other. After six weeks, nobody’s weight had changed, because both diets had just enough calories to maintain it. Another trial went further. One group got 4 percent of their calories from sugar. The other got a whopping 43 percent, with Kool-Aid at breakfast, jelly and marshmallows at lunch and meringue cookies at dinner. Both diets put people in a calorie deficit, and both groups lost about the same weight.
Nobody’s saying a diet full of jelly beans is good for you. But sugar is fattening because of its calories, not because it has some magic fat-storing power other carbs don’t. And lumping all sugar together misses a lot. It’s easy to eat a bag of jelly beans with several hundred calories, but hard to eat several apples in a row. Fruit doesn’t seem to cause weight gain. People who eat more of it tend to hold steady or lose a little, and it fills you up far better than denser sugars.
Sugar also gets blamed for making food addictive. But in one study that ranked foods by how addictive they felt, the worst offenders were high in sugar and fat together. Soda and gummy candy, high in sugar but not fat, ranked lower, and fruit sat near the bottom. Steak, eggs and bacon ranked as more addictive than fruit. Sugar probably isn’t the main culprit.
Sugary drinks do stand out. In one study, people had about 450 calories a day of either jelly beans or soda for four weeks each. After the soda weeks, they’d gained weight. After the jelly bean weeks, they hadn’t, because they naturally ate less of everything else. Soda isn’t more fattening calorie for calorie, but it’s much easier to overdo. So the easiest way to cut back on sugar is to cut back on sugary drinks. Liquid calories are notoriously bad at filling you up. And drinks raise one more big question, and that’s alcohol.
Chapter 11 — Alcohol: The Cost to Benefit Ratio
Alcohol’s calories add up fast. A popular beer has 42 calories per 100 milliliters, and a popular white wine has 72. And people tend to drink these by the pint and the large glass.
Alcohol can also make you hungrier. In one study, a lager with one unit of alcohol before lunch made no difference, but the same lager with four units made people hungrier all day, and they ate more. So one large glass of wine with dinner probably won’t change much, but two or three might. In another study, people ate about 25 percent more pizza and garlic bread when they drank wine before lunch, and 22 percent more when they drank it with the meal.
Alcohol can slow muscle recovery after a workout too. Eating protein with it helps a little. If alcohol knocks muscle building to the floor, protein at least helps it back up to its knees. But one slow recovery doesn’t mean drinking once a month will change a year of training. One speed bump on a long trip doesn’t make you arrive much later. In a study where everyone followed the same workout plan for weeks, changes in fat and muscle were about the same whether people drank or not. Long-term research is still limited.
Drinking a lot can still lead to fat gain, from the calories and from the extra food you eat when it makes you hungry. If you drink heavily, you’re probably holding back your progress in the gym, at least a little.
Chapter 12 — Cheat Meals, Refeeds and Diet Breaks
A refeed means eating a bit more for a day or two in the middle of a diet. Carpenter, who has coached clients for more than a decade, points out that lots of people already do this. It’s called the weekend. They eat carefully Monday to Friday and eat more on Saturday and Sunday.
One trial compared dieting every day with dieting five days a week and refeeding for two. Fat loss was about the same. But the refeed group kept more muscle and better protected their metabolism. In short, refeeds might help you keep more muscle. Maybe.
Diet breaks stretch the idea out, with longer periods of eating enough to maintain your weight. They could help with fat loss, but the whole diet takes longer. Would you rather diet for 16 weeks straight, or for 30 weeks with breaks mixed in? One being better only matters if you’ll actually follow it. It’s normal to want more food on some days, when you’re hungrier or have social plans, so that flexibility makes sense.
Cheat meals are different. Carpenter strongly discourages cheat days, where you give yourself a free pass to eat unlimited amounts of foods you normally ban. If you’re counting down to a cheat day to eat one particular food, ask whether banning it the rest of the week is doing more harm than good.
Chapter 13 — Can Keeping Track Keep You on Track? The Science of Self-Monitoring
Keeping track of things like your weight and what you eat has been called “the cornerstone of behavioral treatment for weight loss.” Think of a business owner trying a new strategy. If they watch their profits, they can see whether it’s working and change course if it isn’t.
The easiest thing to track is your weight. The scale can’t tell fat from muscle, and home body fat tools aren’t very accurate. Using skinfold calipers on yourself is about as reliable as a blindfolded monkey throwing darts. Your weight also moves around with your menstrual cycle, what you ate for dinner and whether you’ve been to the bathroom. That’s one of a bazillion reasons not to obsess over it. Still, weighing yourself regularly has been shown again and again to help. If the number trends down over time, you’re in a deficit. If it trends up, you’re not. But it isn’t right for everyone, because health is about much more than weight.
Food tracking is the other big tool. In one study, 93 percent of people tracking on a smartphone stuck with it, compared with about half of those using a website or a paper diary. An app does the math for you, and most people carry a phone but not a notebook. If you have no idea how many calories you eat, learning the numbers for your usual foods can be eye-opening. Just know that perfect tracking is almost impossible. In some countries, food labels can be off by up to 20 percent, and weighing every ingredient you cook with could be terrible for your mental health.
Even rough tracking helps. You don’t need to know exactly what you spend each day for checking your bank balance to be worth it. Tracking is a tool, and not everyone needs to use it. You can improve your health and lose fat without ever counting a calorie.
Chapter 14 — What Else Can Affect Weight Loss?
Beyond food and exercise, sleep is a big one. In one study, after four hours of sleep instead of eight, people ate 22 percent more food, or 559 extra calories. Some ate even more, and a few ate less, which shows how differently people react. Short sleep won’t stop you losing weight, but it can shift the loss away from fat and toward precious muscle.
In one study, people trying to sleep better were given simple advice. Keep your bedroom dark, quiet and cool. Go to bed and get up at the same time every day, early enough for eight hours. Get natural light as soon as you wake up. In the two hours before bed, dim the lights, put screens away and skip exercise, food and caffeine. Good sleep can help control your appetite, help you keep muscle while dieting and increase how much fat you lose.
Drinking water before meals can help a little. As one team of researchers pointed out, it’s about as easy as weight loss advice gets. Carpenter’s worry is that some people will drink far more than they need just to override their natural hunger.
How fast you eat matters too. In one study, people ate the same meal about 20 percent faster when the food was mashed, and took in more calories. Same food, same taste, just a different texture. In another, chewing each bite 40 times instead of 15 meant eating 11.9 percent less. And when a meal was paced to last 24 minutes instead of six, people ate 25 percent less when offered cookies and chips three hours later. Nobody’s asking you to eat with a beeper. But foods you eat quickly are easier to overeat, which may be part of why people overeat ultra-processed junk food.
Distraction adds up too. People ate 11.6 percent more while watching TV or listening to an audio story, even though they weren’t any hungrier. Try eating dinner at the table instead of in front of the TV, or stepping away from your laptop at lunch. You may notice your hunger more and feel less hungry, without changing what’s on your plate.
Whatever your goal is, it’s time to say goodbye to overhyped, short-term fad diets and hello to smart choices that are best for your health in the long run. And it’s time to stop quietly sacrificing your well-being just to fit into a pair of skinny jeans or see a certain number on the scale. There are better things to do with your life than constantly worry about how much you weigh.