GLP-1 Medications and Nutritional Deficiencies: Why Nutrition Support Matters for Weight Loss in Fertility, Postpartum Recovery, and Perimenopause

GLP-1 medications such as Ozempic®, Wegovy®, and Mounjaro® are increasingly used to support blood sugar regulation and weight loss.

These medications work in part by reducing appetite - which often leads to people eating significantly less food overall.

While this can support fat loss, it may also unintentionally reduce overall nutrient intake. When food intake drops, nutrient intake often drops alongside it.

Reduced Appetite = Reduced Nutrient Intake

Research shows that individuals using GLP-1 medications tend to eat approximately 20–40% less food overall.

A recent systematic scoping review published in Obesity Reviews (2026) examining nutrition strategies alongside next-generation incretin therapies found that across 12 clinical trials:

• Energy intake decreased by 24–39%

• Lean tissue loss accounted for up to 40% of total weight reduction

• Only 3 of 12 studies involved nutrition professionals

• Systematic assessment of protein or micronutrient intake was rare (1)

Despite meaningful weight loss outcomes, detailed dietary intake were rarely monitored in these trials.

What Happens to Nutrient Intake When We Eat Less?

Although most GLP-1 trials do not directly measure micronutrient status, modelling studies of reduced energy intake suggest that when individuals consume 20–40% fewer calories:

• Over 90% of adults may fall below recommended intake for nutrients such as vitamin D

• Potassium intake becomes inadequate in the majority of individuals

• Fiber intake often drops to approximately 40–60% of recommended intake

These patterns have been observed in population-based dietary intake modelling studies examining reduced caloric intake scenarios (2,3).

When overall food volume or meal frequency decreases, intake of the following nutrients may also decline:

• Vitamin B12

• Folate

• Thiamine

• Iron

These nutrients play important roles in:

• Energy production

• Muscle preservation

• Bone density

• Red blood cell formation

• Nervous system function

• Hormonal health

This becomes especially important in life stages where nutrient needs are already increased, including:

• Fertility

• Pregnancy

• Postpartum recovery

• Perimenopause

Why Nutrition Support Matters During GLP-1 Therapy

Weight loss alone does not necessarily reflect improved overall health.

Narrative reviews examining incretin-based therapies have highlighted that these medications may also contribute to reductions in muscle and bone mass and increase the risk of nutrient inadequacy when nutritional intake is not intentionally supported.

If nutritional intake is insufficient, reduced food intake may increase the risk of:

• Fatigue

• Reduced muscle mass

• Suboptimal bone health

• Hormonal disruption

• Slower postpartum recovery

• Long-term metabolic challenges

GLP-1 medications can be effective tools, but intentional nourishment should be part of the care plan when using them.

Using Food Tracking to Support Nourishment (Without Obsession)

In clinical practice, one strategy that I use to help support nutritional adequacy during GLP-1 therapy is temporary food tracking.

Importantly, this is not done to encourage calorie restriction.

Instead, it allows us to see where your nutrition is at currently and see if we need to support intake of:

• Protein

• Fiber

• Iron

• Vitamin B12

• Vitamin D

For individuals with a history of disordered eating, this process can be adapted to remain supportive.

For example:

• Calorie intake can be hidden from patient-facing app use

• Tracking can focus on nutrient intake only

• Monitoring can be used short-term to guide nourishment rather than long-term control

This helps me ensure that patients remain adequately fueled even when appetite is reduced.

Weight Loss Should Support Your Health - Not Come at the Expense of It

GLP-1 medications can be powerful tools.

But like many medical interventions, they work best when paired with appropriate lifestyle and nutritional support.

Working with a qualified provider to monitor protein intake and micronutrient status may help ensure that weight loss supports your:

• Energy

• Bone health

• Hormone balance

• Muscle mass

• Long-term metabolic resilience

rather than compromising it.

Here is a complimentary recipe booklet tp help you get started.

glp-1-30g-protein-8g-fiber-1mcg-b12-0-5mg-thiamine-100mcg-folate.pdf

Download PDF • 2.35MB

👉 If you’re in Mississauga or Milton and need support navigating GLP-1 use, I’d love to help. As a Naturopathic Doctor and birth doula, I support women through fertility, pregnancy, postpartum, and perimenopause with strategies that are sustainable and realistic.

Book here

REFERENCES

1. Spreckley M, Ruggiero CF, Brown A. Nutrition Strategies for Next-Generation Incretin Therapies: A Systematic Scoping Review of the Current Evidence. Obes Rev. 2026 Jan 7:e70079. doi: 10.1111/obr.70079. Epub ahead of print. PMID: 41500509.

2. Bailey RL, Fulgoni VL 3rd, Keast DR, Dwyer JT. Dietary supplement use is associated with higher intakes of minerals from food sources. Am J Clin Nutr. 2011 Nov;94(5):1376-81. doi: 10.3945/ajcn.111.020289. Epub 2011 Sep 28. PMID: 21955646; PMCID: PMC3192481.

3. Blumberg JB, Frei BB, Fulgoni VL, Weaver CM, Zeisel SH. Impact of Frequency of Multi-Vitamin/Multi-Mineral Supplement Intake on Nutritional Adequacy and Nutrient Deficiencies in U.S. Adults. Nutrients. 2017 Aug 9;9(8):849. doi: 10.3390/nu9080849. PMID: 28792457; PMCID: PMC5579642.

4. Barana L, De Fano M, Cavallo M, Manco M, Prete D, Fanelli CG, Porcellati F, Pippi R. Nutrition and Physical Activity in Optimizing Weight Loss and Lean Mass Preservation in the Incretin-Based Medications Era: A Narrative Review. Nutrients. 2025 Dec 31;18(1):131. doi: 10.3390/nu18010131. PMID: 41515247; PMCID: PMC12787956.