Starting a GLP-1 This Spring? Do These Four Things First

You've made the decision. Maybe the appointment is booked, maybe the pen is already in your refrigerator door. Either way you're starting a GLP-1 this spring, and you're picturing how you want to feel by July.

That July date is the part I want to talk about.

Not to talk you out of it. These are legitimate tools, and I've watched them quiet food noise nothing else touched. But a deadline changes how people use them. It makes you want the dose higher and the scale faster.

Speed is where the damage happens.

Most of the people I work with come to me after they've already started. Preparation is rarely part of the handoff. You get a prescription, a titration schedule, and a follow-up in three months. Nobody mentions that the four weeks before your first dose are the most useful of the year.

So let's talk about what's about to happen, and what to set up while you still have your appetite.

What the medication is about to do to your intake

GLP-1s work in two places at once. They slow gastric emptying, so food sits in your stomach longer and you feel full sooner. They also act on appetite signaling in the brain, which is why the mental chatter about food goes quiet.

That's the intended effect, and for most people it works. Response varies more than the headlines suggest, and some people feel very little.

The catch is that your intake doesn't taper. It drops within days, and it drops hardest on the foods that are hardest to eat when you're full and queasy. Protein is at the top of that list.

Then your body reads rapid loss as a stress signal and deprioritizes whatever it considers nonessential. Hair growth is nonessential. Muscle gets broken down for fuel.

A real share of what comes off on these medications is lean tissue rather than fat. How large a share depends on how fast you lose it, how much protein you eat, and whether anything is asking your muscle to stay.

That isn't a flaw in the drug. That's what happens in any steep deficit with no protein and no training stimulus arguing for you.

You can't opt out of appetite suppression. That's the mechanism you're paying for. What you can do is build the four systems that have to survive it.

1. Get your baseline while you still have one

Once you're twenty pounds down, you cannot go back and find out what your ferritin was.

Low iron stores, low B12, low vitamin D and low zinc all produce fatigue, weakness, shedding hair and flat mood. Those are the symptoms people later blame on the medication. Without a baseline you'll spend six months guessing.

Ask your physician for a panel first:

• CBC and CMP
• Ferritin, not just hemoglobin
• Vitamin D
• B12
• Zinc, and RBC magnesium if available
• A1c, fasting glucose, fasting insulin
• Lipids
• TSH and free T4

Vitamin D is worth checking whatever the month happens to be. In the northern half of the country the sun angle from roughly October through March doesn't allow for much skin synthesis, so stores drift down over winter and take a while to come back. A number on paper beats a guess about your sun exposure.

Then get a functional baseline, because labs tell you half of it. A DEXA scan is the gold standard. If you can access one, this is the week. If you can't, write down three things your body can do today. How many push-ups. What you can carry up a flight of stairs. How many times you can stand out of a chair without your hands.

2. Build the protein habit before you lose the appetite

During active weight loss the range I work in is roughly 0.7 to 1.0 grams of protein per pound of goal body weight. For a goal weight near 140 pounds that lands between 100 and 140 grams a day, or 25 to 40 grams at every eating occasion.

Read that again and picture doing it on the fourth day after an injection.

This is why the prep window matters. Protein is not a number you hit by intending to. It's a short list of foods you can tolerate when you have no interest in eating. Greek yogurt. Eggs. Cottage cheese. A shake you have actually tasted.

Spend the next few weeks finding yours, while your appetite is still there to help you. Building this habit after your first dose is like trying to organize the kitchen while dinner is burning.

And when you start, don't cut calories further than the medication already does. I see this mistake constantly, usually in people with a date on the calendar. Eat to satiation, put protein first, and trust the medication to do its job.

3. Start lifting before the deficit starts

Without a training stimulus, muscle mass declines steadily from your thirties onward, and the losses pick up speed later in life. Severe muscle loss has a name, sarcopenia, and it sits underneath falls, fractures and lost independence later.

Resistance training is the clearest signal that this tissue is in use and should be kept. Protein and daily walking help, and neither one argues for your muscle the way load does.

Two to four sessions a week. Squat, hinge, press, row, carry. Add load over time.

Start now for a practical reason. Learning to hinge is much easier while you're eating normally than it is once your appetite is gone and your stomach is unsettled. Begin this month and by week eight you're maintaining a habit, not starting one.

When your intake drops, do not drop your training with it. That instinct is backwards. This is when training matters most.

I want to be clear about what this is for. You're not lifting for the summer. You're lifting so you can still carry your own groceries at 80.

4. Set up your gut before it slows down

Slowed gastric emptying is the same mechanism that makes you feel full, so constipation isn't a side effect you can engineer away. You can only get ahead of it.

Hydration is not optional here. Most people land somewhere around 80 to 100 ounces of fluid a day, more once the weather turns. If you have heart failure or kidney disease, or you take a diuretic, your fluid target belongs to your physician rather than to a number in a blog post.

Fiber needs a ramp, not a jump. Adding a lot of fiber to an already sluggish gut makes things worse, and fiber without water makes constipation harder, not easier. Start now with soluble sources like chia, ground flaxseed, oats and cooked vegetables. Build that tolerance this month. You can't build it during week two of nausea.

Magnesium citrate is the one people ask about, because it pulls water into the bowel and has a gentle laxative effect. The doses that show up in practice run 200 to 400 milligrams in the evening.

Whether it belongs in your routine, and at what dose, is a question for your prescriber or pharmacist. Magnesium accumulates when kidney function is reduced, and it interacts with several common medications.

Intakes below the recommended amount are common, which is not the same thing as a measured deficiency. That's what the RBC magnesium on your panel is for.

Then walk daily. A sedentary gut is a sluggish gut.

What about supplements

Creatine monohydrate has solid evidence for supporting muscle and strength alongside resistance training. It's inexpensive and worth starting now. Vitamin D is worth supplementing if your labs say so.

But no supplement replaces protein, resistance training and water. Those are the foundation.

When to call your prescriber

I'm a dietitian, not your physician. Dose decisions belong to whoever wrote the prescription. What you should have going in is a clear sense of when to call.

Call if you're consistently losing more than about one percent of your body weight per week. Call if you're vomiting and can't keep food or fluids down. Call for severe or new abdominal pain, constipation that hasn't responded after two weeks, or any symptom affecting your daily life.

They have real options, including a slower titration, holding at a dose longer, switching agents, or supportive medication. That call is theirs to make with you.

A different scorecard for this summer

If the scale is the only number you watch, the medication will look like it's working right up until the day you can't get off the floor without your hands.

So track a few other things. Grams of protein you actually hit. Your three strength numbers. Sleep and recovery. Labs again at three and six months. Whether stairs feel easier than they did in April.

These are the numbers we watch with clients on GLP-1s. They are the ones that still matter in twenty years.

For most people the scale moves. It is still the least interesting number you have.

The bottom line

These medications can do something genuinely useful for your metabolic health. But a tool has a mechanism, and a mechanism has a cost. Left unmanaged, you can solve excess fat and create inadequate muscle.

Four weeks of preparation is where you get a say in that math. Labs, a protein habit, a barbell and a fiber ramp. None of it is complicated. All of it is much harder to start once your appetite is gone.

You deserve to feel strong through this, not depleted.

If you'd rather build the plan before your first dose than after your first problem, that is exactly what I do.

Emily