How to Eat to Lose Weight

When it comes to eating for weight loss, two things matter: WHAT you eat (ie macronutrient balance: protein, fat, and carbs) and HOW MUCH you eat (ie calories). You can’t get around the fact that a calorie deficit is essential for losing weight. You can eat the most healthy/vegetarian/organic/low-carb/unprocessed/raw/paleo diet in the world, but if you’re not eating at a deficit then you won’t lose weight, and you might even gain. At the same time, a calorie deficit alone might make the scale go down, but if you ignore nutrients and balance then you won’t be healthy, it’s unlikely to be sustainable, and you’ll never actually get the body you probably want.

The approach I use isn’t the only one, but it’s a good place to start. It’s a very basic and flexible plan that can be adapted to almost any eating style, and will easily become intuitive as you transition into maintenance. The way I present things might seem a little out of order, but reflects the approach that I take to how I eat and how I believe people should eat.

First, a quick rundown of the three macronutrients:

  1. PROTEINS – have 4 calories per gram
  2. FATS- have 9 calories per gram
  3. CARBOHYDRATES – have 4 calories per gram
Some foods fall pretty clearly into one category (ie butter is a fat, egg whites are protein, fruits are carbs) but many fall into more than one. An internet/phone application like LoseIt, MyFitnessPal, etc is pretty much essential for tracking these–otherwise it’s going to be wayy too much work.


1) Protein: 

Eat one gram of protein per pound of your ideal body weight. Multiply this number by 4 for the number of protein calories you should eat each day.

For example, let’s say my ideal body weight is 130 lbs (that’s the lowest I’d ever want to go). So I should eat 130 grams of protein per day, or 130 x 4 = 520 calories from protein.

2) Fat:

Eat .3 to .5 grams of fat per pound of your ideal body weight. Multiply this number by 9 for the number of fat calories you should eat each day.

I should eat between 130 x .3 = 39 grams of fat and 130 x .5 = 65 grams of fat–I’ll say 50 grams. 50 x 9 = 450 calories per day.

**NOTE: You might have noticed that so far we haven’t taken into account your starting weight, how much weight you want to lose, or how many calories you’re eating. These are your BASELINE amounts of protein and fat regardless of how much you weigh, want to lose, or how much you eat. So how do you lose weight? By manipulating your carbohydrate intake, as follows:

3) Carbohydrates:

Determining your ideal carbohydrate intake requires working backwards.

Step 1: determine your BMR (Basal Metabolic Rate, ie the number of calories you’d burn if you laid in bed all day). You can use an online calculator like this one

I input my age (21), height (5’8), and weight (140) for a BMR of 1485.

Step 2: Multiply this number by your activity level to determine your calorie maintenance needs.

Harris Benedict Formula

To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:

  1. If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
  2. If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
  3. If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
  4. If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
  5. If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

Right now I’m going to say I’m moderately active and multiply by 1.5, for a daily maintenance level of about 2225.

**NOTE: Already you can see that this is only going to produce a rough estimation–this BMR calculator doesn’t take into account muscle mass or metabolic differences, and determining an activity level is pretty subjective. But that’s okay because it’s just a starting place.

Step 3: Figure out the caloric deficit you need for your weight loss goals (1 lb ~ 3500 calories) and subtract this number from your calorie maintenance level to determine your daily calorie goal.

Let’s say I want to lose 5 lbs per month, or 1.25 lbs per week. 1.25 x 3500 = 4375 calorie deficit per week, or 625 per day. 2225 – 625 = 1600 calories per day.

**NOTE: You know how you always hear that you’re not supposed to lose more than 2 lbs per week? Well, you can see why. 2 lbs per week is a 1000 calorie deficit per day, and you’d have to be eating a lot already to create this much of a deficit without going below your basic nutrient needs–it’s not realistic unless you’re starting out as overweight or obese. Also, if your weight loss goals put you below 1200 calories per day, you need to change your goals–1200 calories is NOT as much as you think, and your body will thank you in the long run.

Step 4: Subtract your protein and fat calories from your daily calorie goal to determine how many carbohydrate calories you can eat. Divide by 4 to find daily grams of carbs.

1600 – (520 + 450) = 630 calories from carbs per day. 630/4 = 158 grams of carbs per day.

So let’s review: if I am a moderately active 5’8, 140 lb, 21 year old girl and I want to lose 1.25 lbs per week, I should aim for an average of 1600 calories per day made up of 130 g protein, 50 g fat, and 158 g carbs (a ratio of approximately 32% protein, 28% fat, and 40% carbs). Does this mean if I follow this formula exactly, I will automatically lose 1.25 lbs every single week? NO. Your body is not a calculator, fat loss is not linear, and it’s not always reflected accurately by the scale. Moreover, many of the inputs will vary from person to person, PLUS the lower your weight, the harder it becomes to lose, and most people have a threshold that it’s going to be pretty much impossible to get below (I may never weigh 130 lbs for example–it’s just an easy number to use to illustrate). Also, it’s pretty much impossible to follow this exactly–this is just a starting point.


So once you’ve figured out your desired calorie and macronutrient intake, you could just decide to eat the same amount every day, which is what a lot of people do. However, I prefer to vary my intake from day to day based on my natural hunger levels, what I’m doing that day, whether I’m eating out or in, etc. So I think about my nutrient needs on a weekly basis, not a daily basis–ie I want to be eating 11,200 calories per week, made up of 910 g protein, 350 g fat, and 1100 g carbs.

First of all, I’m going to subtract 1000 calories per week for alcohol (including mixers). Because I drink and party, that’s a part of my lifestyle and I’m not just going to put that on hold. If I tried to fit alcohol calories into the days I drink, it wouldn’t leave me enough space for food on those days, so I’m just going to take it out from the get-go. 1000 calories is just an estimate and varies week to week–some weeks I don’t drink at all, and some weeks *cough spring break last week cough* I probably drink that much daily–but it should average out on a monthly basis. Those calories are basically all carbs, so I’m going to subtract 1000 calories and 1000/4 = 250 g carbs from my weekly goals, leaving me with 10,200 calories per week with 910 g protein, 350 g fat, and 850 g carbs (for a food ratio of about 36% protein, 31% fat, and 33% carbs)

Now, I could just divide 10,200 calories evenly across the week for about 1450 calories per day, but I don’t want to do that, because again my needs/wants vary day to day. I prefer to calorie cycle, eating lower-calorie 4-5 days a week and higher-calorie 2-3 days a week). For example, I might average 1200 calories 5 days per week, and 2100 calories 2 days per week. (*Actually, I honestly eat more than this–more like 1200 calories 4 days per week, 2000 calories 2 days per week, and 3000 once a week–I’m just trying to make the numbers work out for the purpose of the example)

As far as dividing up your macronutrients, you can vary that too. When I eat more, I tend to eat more of EVERYTHING, so my ratios are consistent–if I eat 3000 calories for instance, it’s about 250g protein, 100g fat, 300g carbohydrates. However, you might prefer to save your carbs for the higher calorie days to indulge in baked goods, bread, etc–it’s whatever works!


1. I don’t follow this exactly–it would be impossible! It’s just a good starting place for thinking about your needs. Chances are you will want to tweak your deficit goals, nutrient ratios, and weekly division depending on what’s working for you. And once this style of eating becomes natural, you probably won’t need to track at all–it will just be intuitive (I didn’t track at all while maintaining my weight last year, because I didn’t know about the phone tracking apps).

2. Note that this says nothing about WHAT foods to eat. You can adapt this approach to any lifestyle–vegan, vegetarian, paleo, raw foods, organic foods, etc. Also, note there is nothing that you HAVE to eat or nothing that you CAN’T eat on this plan. Granted you might have trouble eating an ice cream sundae with 200 g carbs if your daily goal is only 150 g, but if you want to make it work on a weekly basis you totally can. There are literally no foods that would be considered “cheat” foods (I hate that term anyway–you’re not “cheating,” you’re eating!). Therefore I believe it’s a psychologically healthy way to think about food for life–not just temporarily.

3. That being said, this is designed for the “average” person. If you’re training to run a marathon, or to compete in a bodybuilding competition, or you have special medical needs, then your needs might be different, and I’m not even going to attempt to comment on them–talk to a coach, trainer, doctor, or at least just look to a blogger that has experience in your personal needs!

4. This also doesn’t address/account for exercise (besides accounting for your activity level). Exercise is SO important for getting and keeping the body you want, it’s just too much to address in one post.

5. Don’t eat back your exercise calories if you’re doing this – because you’re already accounting for them in your activity level. All calorie levels refer just to intake calories, not “net” calories. (I’m going to post later why I fundamentally disagree with eating back  exercise calories.)

I hope this was helpful and please feel free to message me if you have any questions!!


2 Responses

  1. Thank you!!! This is AWESOME info – very, very helpful!!! I wish they’d taught us this in HS instead of some of that useless stuff we covered in health class.

    I took notes. I’m making some changes. You rock!! Thanks for taking the time to write this out.

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